Mass and thermal diffusivity algorithms: reduced algorithms for mass and thermal diffusivity determinations

Area of Science:

• Materials Science
• Physics
• Space Science

Background:

• Earth-based diffusivity measurements are hindered by convection.
• Spacecraft studies show reduced convection enhances measurement precision in low gravity.
• Limited experiment time in low gravity necessitates efficient measurement techniques.

Purpose of the Study:

• Develop and validate real-time diffusivity measurement techniques.
• Enhance precision and efficiency for low-gravity research.
• Enable multiple diffusivity measurements from a single sample.

Main Methods:

• Mass diffusivity: Radiotracer in a cylindrical sample, radiation intensity measured via collimators and detectors over time.
• Thermal diffusivity: Heat pulse in a disk sample, temperature response measured at multiple locations.
• Real-time data acquisition allows multiple measurements per sample at various temperatures.

Main Results:

• Developed and extensively tested real-time techniques for diffusivity measurements.
• Achieved higher precision and lower absolute values compared to Earth-based methods.
• Methodologies are experimentally simpler and more robust, especially for limited low-gravity experiment durations.

Conclusions:

• Real-time diffusivity measurement techniques offer significant advantages for low-gravity research.
• The developed methods provide precise and efficient data acquisition.
• These techniques overcome limitations of traditional methods, enhancing scientific discovery in reduced gravity.