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### Pulverize with sonic energy or when the fat lady sings.

04/04/2009 9:52 PM

Engineers:

How do you determine the resonant frequency of a material? What if it is not a crystal? Can the material be measured if frozen in liquid N?

This is leading to the question: can one pulverize a material with sonic energy that is frozen?

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#1

### Re: Pulverize with sonic energy or when the fat lady sings.

04/05/2009 12:59 AM

The best way to determine the resonant frequency is by experiment. Hit the object and measure the vibration response. The frequency it vibrates at is its natural frequency.. When you then apply energy at that same frequency you will have a resonance condition.

I assume your question is actually, Can one use sonic energy to pulverise a material that is frozen? The answer is yes. Hook up a speaker to a function generator, start to vary the output frequency of the function generator, and when you get a strong sympathetic vibration in the material you have found the natural frequency. Then it is just a matter of generating sufficient sound intensity... Which may be easier said than done depending on what the object is..

(BTW this is not the thread on demolishing a bathtub resurrected is it??)

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#2

### Re: Pulverize with sonic energy or when the fat lady sings.

04/05/2009 1:03 AM

(BTW this is not the thread on demolishing a bathtub resurrected is it??)

Nope. The bathtub thread creeps on, even tho Tubby is long gone.

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#3

### Re: Pulverize with sonic energy or when the fat lady sings.

04/05/2009 4:03 AM

The resonant frequency is less about the material, more about the shape. You can make a bell out of brass to ring at just about any (audio) frequency you want.
You can make a quartz crstal resonate at different frequencies depending on how it is cut.

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#4

### Re: Pulverize with sonic energy or when the fat lady sings.

04/05/2009 7:30 AM

Right, and I would add the size. You can make a quartz resonate at lower frequencies (under 100 KHZ) but to get some measurable signal, THE SIZE MATTERS!

BTW, a lead bell has a very "dull" sound, at 273 K, but at 180 K things change...On the other hand, at 277 K, my favorite Cabernet has the lowest viscosity (the fastest flow)...rrr...what was I talking about?

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#5

### Re: Pulverize with sonic energy or when the fat lady sings.

04/05/2009 8:16 AM

can one pulverize a material with sonic energy...

this is off the track of "resonant frequency" of the material, but there are medical technologies using ultrasound to 'pulverize' ? stuff:

If you search PubMed for "HIFU" that is high intensity focused ultrasound, you'll find a literature on it. The term "cavitation" is also used.

Here's an abstract about acoustic cavitation in HIFU for example.

Don't know if something like this would be powerful enough to pulverize the material you're thinking of. From what I've read, the therapeutic use of HIFU takes time because the physical effects are small (search confocal re: efforts to make it more efficient, using dual frequencies). There's also something called HESW high energy shockwave, and shockwave therapy used to break up kidney stones.

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#6

### Re: Pulverize with sonic energy or when the fat lady sings.

04/05/2009 9:12 AM

artsmith,

I am very familiar with HIFU. On 1-16-07 I had my prostate cancer removed with this procedure. Your right it takes a while, in my case I was 'out' for about 3 hours. The procedure is VERY controlled, all done by computer. I woke up, walked out and my wife and I went out to supper. Next morning I felt fine. Thought these people have some good kind of drugs they shot me up with, so while I was feeling good we walked the beach for 3 hours. Advice, do not go out without sunblock on your nose. The drugs they shot me up with were antibotics.......makes you sensitive to sunlight.

To make a long story short, the HIFU procedure was a complete success, the only thing I felt was a little guilty for having escaped a very life treating situation with no pain and no after effects. This was a bad case, most doctors said I was too late for surgery and seed implant. (stage 3, gleason 7+, and cancer was just about to escape the prostate wall). From 60 days after my procedure until the present my PSA has been 0.02, that is super.

You are right HIFU or maybe evan better would be the kidney stone blaster.

I will look into this.

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#7

### Re: Pulverize with sonic energy or when the fat lady sings.

04/05/2009 9:44 AM

thanks for sharing the personal HIFU experience - and congrats it worked so well! It sounds like it has great potential as a non-invasive surgical tech, and will probably replace many of the more invasive surgeries in the future. (We have nothing like this in the area where I live, yet, afaik. The public healthcare sucks...)

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#8

### Re: Pulverize with sonic energy or when the fat lady sings.

04/06/2009 8:52 AM

Every winter the weather forecasters in Fargo, North Dakota, USA step outside with a cup of liquid and throw the liquid into the air and the liquid turns into snow, freezing in mid-flight.

The science shows also demonstrate freezing something with liquid nitrogen or sometimes CO2, and then tapping the material and watching it shatter.

So this relates to your super-cooling/freezing a material and then trying to determine the resonant frequency, probably just won't happen. A Twinkie has a completely different hardness coefficient at 25C, -10C, -273C which will yield very different sounds, which sound are you searching for ?

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#9

### Re: Pulverize with sonic energy or when the fat lady sings.

04/06/2009 10:23 AM

Corona Man,

We are looking for the sound or resonant frequency that we can excite with a matching frequency from a sonic device. This matching frequency will be so powerful that it will pulverize the target material. (The fat lady sings and breaks the wine glass) In our case the target material is smaller than a wine glass but it is not a crystal but it is hard. Therefore to make it harder we freeze it in liquid N. Sorry I can't tell you what the material is, still working on the patent application.

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#10

### Re: Pulverize with sonic energy or when the fat lady sings.

04/06/2009 10:49 AM

Starting from the basics, at resonance a serial circuit (L,C) will draw the maximum power while a parallel circuit (L,C) will draw no power at all (ideally). See the way you excite your stone or whatever you freeze, and try to get a the resonance frequency from the consummated power.

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