Portugal uses ultrasonics to identify paper quality

The University of Aveiro, Portugal recently invented a method that uses ultrasonics to analyze the carbon content of paper to identify paper quality.
According to reports, the currently used method can only detect the orientation of the fibers in the paper, and cannot obtain the carbon content index. As the addition of carbon to the paper can increase paper quality and the cost of carbon is lower than wood fiber, this has become a common method in paper manufacturing.
The person in charge of the development project said that the wavelength of the ultrasonic wave is between 1 mm and 300 mm, and the speed of propagation in the material varies depending on the nature of the medium. The more uniform the composition of the material, the smaller the porosity, the faster the ultrasonic wave will travel. Ultrasonic waves travel four to five times faster in the carbon composition than in the wood fiber. Through this difference, the amount of carbon in the paper can be measured to determine the quality of the paper.
Also involved in this development are experts from the University of Coimbra, Portugal. They believe that this technology can be widely used in the work of the paper quality control laboratory.