I am using a Cole-Parmer 750-Watt Ultrasonic Homogenizer. Is it possible to control the frequency of the ultrasonic oscillation on this machine or do I need other pieces of equipment?
I am attempting to make translucent oil in water nano-emulsions following the protocol in this paper. My oil to water ratio will be significantly more however, it needs to be as high as possible while remaining translucent.
The energy setting of my homogenizer its in Joules.
So how do I convert from Hz to J ??
Here are the numbers form the paper but it doesn't make sense to be me because how can a higher frequency have a lower energy if E=hv?
20 kHz 44W cm^-2 = 440000 J
1.6 MHz 16W cm^-2 = 160000 J
2.4 MHz 7W cm^-2 = 70000 J
Here is their method
0.5 mmol of EDOT was added to 25 mL of aqueous solution containing 1.0 M LiClO4 in glass beaker cell. The 20 kHz ultrasonication to the water/oil mixture was conducted with an ultrasonic stepped horn (13 mm diameter, titanium alloy) connected with a 20 kHz oscillator (44 W cm−2, SONIFIER-250D, Branson Ultrasonics Co.) for 5 min. The sequential ultrasonication with 1.6 MHz treatment after 20 kHz was carried out using an ultrasonic transducer (16 W cm−2, Honda Electric Co.) connected with a Pyrex glass cylindrical tube (diameter, 24 mm; length, 75 mm) for 5 min. The further sequential ultrasonication with 2.4 MHz treatment after 20 kHz and 1.6 MHz was conducted by an ultrasonic transducer (7 W cm−2, Honda Electric Co.) connected with a Pyrex glass cylindrical tube (diameter, 24 mm; length, 75 mm) for 5 min.
Your Cole Palmer homogenizer probably operates at a fixed frequency of 20 kHz (High power, low frequency). This cannot be changed it is dependent on the physical mass and construction of the transducer. Transducers can designed to have more than one resonance point but you need a second generator to make it function. Multi high frequency transducers are availabile. This is what has been used after the first sonication Step. If you want to follow the above procedure you need to use a high frequency system such as this one below:
https://www.meinhardt-ultrasonics.com/english/ultrasonic-products/multifrequency-system-mfg/
Your Cole Palmer homogeniser cannot be adjusted to operate at high frequency.
How would you ever "convert from Hz to J ??" This is a pure nonsense, energy is energy (Kg*m2*s-2) and frequency is frequency (s-1).
Energy conservation is the basic law of our universe: electric input joules will be spread between thermal losses in the electronics and probe and the fewer turned into mechanical vibration of the piezoceramic. A fraction of it will turn ultimately into ultrasound. This is true at any frequency, however some of the losses and conversion factors are frequency-dependent. In addition, at high level the probe might behave non-linearly, and even could reach the cavitation threshold which add another loss phenomenon which is vaporisation then implosion of the micro-bubbles at the probe interface with your mixture.
The homogeneization however is not facilitated by the ultrasound energy but the ultrasound particle velocity: if your probe is built as a tuned resonator, which I would expect, you gain from energy to particle velocity with the Q factor of this probe resonance ("tuning").
The simplest I would do to quantify your trials would be to add a miniature hydrophone in your mixture and measure the ultrasonic sound pressure as insonification level reference whatever probe you use and amplification you set. Your attempt to quantify the whole chain would require you to go back to a school bench for another 5 yrs at least...
https://www.honda-el.co.jp/en/industry/HM-2412-e1.html
I was thinking of getting one of these ultrasonic transducers and then hooking it up to a power supply and putting it facing down at the bottom of a tube and submerging it in the liquid similar to the existing probe.
Worth a try if they're not too expensive. Don't forget if you're following the paper you need to operate at 1.6 and 2.4 MHz so you will need to purchase a unit for each frequency. Let me know if it works.
Good luck :)
same probe should be ok as frequencies are close, just adjust the sensitivity according to the calibration curve! It is not a power supply you need but a charge amplifier (used as a sensor, the piezo-electric probe convert ultrasonic sound pressure into electric charges (pico-coulombs) and you have to use a charge amplifier to get volts/kPa)
how can I calculate the power in watts from amplitude Bernard Garnier ier
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