Nuclear Magnetic Resonance (NMR) is a well-established technique for measuring moisture content in a variety of materials, including paper. It is a non-destructive and non-contact method that can provide accurate and reliable results.
NMR relies on the magnetic properties of atomic nuclei. When a material is placed in a magnetic field, the nuclei of certain atoms, such as hydrogen, align themselves with the field. By applying a radiofrequency pulse to the material, the nuclei are excited and begin to resonate. The resonant frequency of the nuclei is proportional to the strength of the magnetic field and the type of atom.
In the case of paper, the hydrogen nuclei in the water molecules are detected. The amount of water in the paper can be determined by measuring the intensity of the NMR signal, which is proportional to the number of hydrogen nuclei present.
NMR is used in a variety of applications for paper moisture analysis, including:
NMR is a powerful tool for measuring moisture content in paper. It is a non-destructive, non-contact method that can provide accurate and reliable results.