Experimental study of the moisture distribution inside a pulp sheet using MRI. Part I: Principles of the MRI technique

• Due to its real advantages in terms of spatial resolution, the MRI technique has been chosen in order to study the internal moisture in 2.5 mm thick industrial pulp samples. A spin-echo sequence with very short echo-time (TE= 2 ms) has been designed to measure moisture content inside highly hygroscopic materials and was able to detect moisture even at very low moisture content (6%). In order to enhance the spin-lattice relaxation process, and thus reduce the total scanning time of an image, the pulp samples were wetted with solutions containing contrasting agents such as copper sulphate. The optimized value of the copper sulphate concentration was finally found to be around 0.5 gL(-1). A calibration curve was utilized to transform the signal intensity into moisture content values. A slight curvature probably due to shrinkage effects appears in the calibration curve.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Kemiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Chemical Engineering (hsv//eng)

Nyckelord

bibliographies

magnetic resonance

image analysis

moisture content

distribution

pulps

hand sheets

copper compounds

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)