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Thread: Ultrasonic Sound Waves

  1. #1 Ultrasonic Sound Waves 
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    Is it true that they can melt metal?


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  3. #2 I guess its true 
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    I found this quote on a website:

    "Ultrasonic welding involves the use of high frequency sound waves to melt materials"

    So I guess you can say that ultrasonic sound waves can melt metal.


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  4. #3 Re: Ultrasonic Sound Waves 
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    Quote Originally Posted by MoltenWhale
    Is it true that they can melt metal?
    For some reason someone called it ultra sound. However it was into radio frequency. And radio can certainly heat things up.

    Just another bad naming convention in my opinion.

    That is why I have my doubts about the safety of those "ultra sound" cleaning systems.


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    William McCormick
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  5. #4 Ultrasonic Sound Waves 
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    Ultrasonic energy causes heat by vibration and corresponding energy loss. Radio frequency heating may not work on insulating materials however, unless they have a high dissipative loss (loss tangent). Plastic, for example will not heat up much with radio frequency energy compared to a conductive metal rod.

    A microwave oven uses radio waves to "vibrate" water molecules causing heat. It doesn't heat plastic to anywhere near the same extent - allowing "microwave safe" dishes.

    The term "ultra" is relative to the technology of the age. For example, in the old vacuum tube days, "ultra high frequency" i.e. UHF radio waves referred to frequencies beyond 30 MHz. About a decade ago, 30 MHz was just called "High Frequency" or HF and frequencies around 150 MHz were referred to as "Very High Frequency" i.e. VHF. UHF referred to frequencies from ~300 MHz to 1,000 MHz, i.e. 1 GHz. "Microwave referred to frequencies above 1 GHz.

    Recently the terms have been redefined in many countries. UHF refers to frequencies up to 3 GHz. The device technology we enjoy treats 3 GHz as if it were audio - for example, Infineon's BFP620 bipolar transistor has a transition frequency (FT) claimed to be as high as 70 GHz and costs about 50c in standard SOT23 SMD.

    The definition of acoustic frequencies appears to be based more on biolgy than technology. If we retain an upper hearing frequency limit of 20 kHz (at best) then "ultra high frequency" audio will probably remain defined as relating to frequencies greater than 20 kHz.
    "The sky cannot speak of the ocean, the ocean cannot speak of the land, the land cannot speak of the stars, the stars cannot speak of the sky"
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  6. #5 Re: Ultrasonic Sound Waves 
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    Quote Originally Posted by Vaedrah
    Ultrasonic energy causes heat by vibration and corresponding energy loss. Radio frequency heating may not work on insulating materials however, unless they have a high dissipative loss (loss tangent). Plastic, for example will not heat up much with radio frequency energy compared to a conductive metal rod.

    A microwave oven uses radio waves to "vibrate" water molecules causing heat. It doesn't heat plastic to anywhere near the same extent - allowing "microwave safe" dishes.

    The term "ultra" is relative to the technology of the age. For example, in the old vacuum tube days, "ultra high frequency" i.e. UHF radio waves referred to frequencies beyond 30 MHz. About a decade ago, 30 MHz was just called "High Frequency" or HF and frequencies around 150 MHz were referred to as "Very High Frequency" i.e. VHF. UHF referred to frequencies from ~300 MHz to 1,000 MHz, i.e. 1 GHz. "Microwave referred to frequencies above 1 GHz.

    Recently the terms have been redefined in many countries. UHF refers to frequencies up to 3 GHz. The device technology we enjoy treats 3 GHz as if it were audio - for example, Infineon's BFP620 bipolar transistor has a transition frequency (FT) claimed to be as high as 70 GHz and costs about 50c in standard SOT23 SMD.

    The definition of acoustic frequencies appears to be based more on biolgy than technology. If we retain an upper hearing frequency limit of 20 kHz (at best) then "ultra high frequency" audio will probably remain defined as relating to frequencies greater than 20 kHz.
    Beyond 18,000 is radio from what I was taught. I agree it is a biological definition. Snce we are humans I think it should be adhered to.

    However you can create a damaging radio/magnetic transmission with extremely low hertz.

    The whole point of the frequency was just to insure a certain level of safety. If you create a high frequency, source. You risk causing nerve control loss. Even with low energy type emissions.
    Where the same power level would not have harmed someone or allowed them to let go of an energized device, at sound frequencies.

    With high frequency above sound, you can definitely cause destructive effects to the human even with low voltage and wattage. And you can cause strange effects with insulators as well.

    Often these accidents take place through capacitance, often "T" (time) causes an object to become a capacitor. Raising the wattage of what was meant to be a harmless high frequency device.

    Tesla devices can do that.

    You can get stuck to an object emitting high frequency. Because your nerves lock on. And your grip becomes involuntary.



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    William McCormick
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  7. #6 Ultrasonic Sound Waves 
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    Yes William, I agree and I certainly don't dismiss the danger of any radiating source, be it acoustic, electromagnetic or otherwise (thankfully we don't as yet have gravity wave cleaners!)

    I had read that some military investigations have been conducted (if this can be given credit) for inducing patterns of thoughts in the minds of (enemy) people using modulated radio waves. One of the claims was to induce docility in crowds so as to facilitate crowd control. Other claims were to induce uneasiness and panic so as to disrupt aggressive enemy maneuvers.

    Other radio weapons based on high voltage (capacitor based) discharge in a vacuum tube (similar to an x-ray tube) housed in a directional wave-guide antenna were supposedly investigated as a method of wiping electronic equipment out. Lower frequency alternatives based on exploding a strong magnetic field (by dynamite surrounding an electromagnet) were intended to couple large voltage spikes into telephone lines etc and take out connected electronics (e.g. complete telephone networks). Nuclear weapons also produce EMP damage and in the acoustic arena, very low frequencies have been reported to damage internal organs to the point of death.

    No matter how we slice it, the world is (and has always been) a dangerous place. It is wise to research any technology prior to application, assess the risks (if any) and take precautionary measures (if need be).
    "The sky cannot speak of the ocean, the ocean cannot speak of the land, the land cannot speak of the stars, the stars cannot speak of the sky"
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  8. #7 Re: Ultrasonic Sound Waves 
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    Quote Originally Posted by William McCormick
    Quote Originally Posted by MoltenWhale
    Is it true that they can melt metal?
    For some reason someone called it ultra sound. However it was into radio frequency. And radio can certainly heat things up.

    Just another bad naming convention in my opinion.

    That is why I have my doubts about the safety of those "ultra sound" cleaning systems.


    Sincerely,


    William McCormick
    If you see it coming from sound bandwidth (0 to around 20khz) view point, it is proper to say ultra (as defined by the prefix).
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