Developing a self-calibrating system for volume measurement of spheroidal particles using two acoustically levitated...

Area of Science:

• Acoustic levitation
• Fluid dynamics
• Optical measurement techniques

Background:

• Acoustic levitation is used for handling small liquid volumes.
• Conventional volume measurement relies on image analysis with calibration spheres.
• Calibration sphere methods are time-consuming and costly.

Purpose of the Study:

• To develop a versatile and low-cost self-calibrating method for measuring acoustically levitated droplet volumes.
• To provide an alternative to traditional calibration sphere techniques.
• To enable accurate volume determination of nanoliter to microliter droplets.

Main Methods:

• Utilizing a horizontally oriented acoustic trap with two levitated droplets.
• Processing inter-droplet distance via image analysis of real-time or recorded data.
• Employing acoustic field simulation based on temperature to predict scale factor.
• Calculating droplet volumes from pixel data of spheroidal shapes.

Main Results:

• The developed method accurately measures droplet volumes, verified against the standard calibration sphere technique.
• Self-calibration was demonstrated by changing camera zoom, showing negligible effects on volume measurements.
• The method was tested on a modified TinyLev system with two transducer packing types.

Conclusions:

• The self-calibrating method offers a versatile, low-cost, and accurate alternative for measuring acoustically levitated droplet volumes.
• This technique overcomes limitations of conventional static calibration methods.
• The approach enhances the practicality of acoustic levitation applications requiring precise volume control.