Solid-liquid nuclear magnetic resonance relaxation and signal amplitude relationships with ranking of seasoned softwoods and hardwoods

In 1H NMR (Nuclear Magnetic Resonance) relaxation measurements for a set of eight hardwood and softwood samples, each Free Induction Decay (FID) is fit by the sum of a “Solid” signal of the form A exp[−c(t/Ts)2] [1−g(t/Ts)2+h(t/Ts)4] plus a “Liquid” signal B exp(−t/T2 FID). Distributions of longitudinal (T1) relaxation times were computed separately for the Solid and Liquid components, giving also the Solid/Liquid 1H ratio α. From measurements on the samples dried, seasoned, and hydrated, the moisture content, (Liquid/Solid weight ratio) was found to be approximately 0.50/α. For each of the “Seasoned” samples (10-13% moisture content) a single T1 peak was found for the Solid and two for the…

NMR relaxation in modern wood and treated and untreated wood from a XVI century wooden statue

Longitudinal (T1) relaxation data are presented for European lime (Tilia cordata Mill) wood samples, a modern sample and two from a XVI century wooden statue, one of which samples is treated with Paraloid B72 for preservation. The 1H signals from liquid and solid are separated in the free induction decays (FID). T1 distributions are obtained by UPEN and show two resolved peaks for the liquid component of either untreated wood but a wide distribution for the liquid of the treated sample. In each case, the solid component showed a single peak, which for either untreated sample was at about the position of the longer T1 liquid peak. We compute geometric-mean times, T1-gm, 2.1 and 36 ms for the…

Misure di rilassamento 1H-NMR per la classificazione di essenze lignee e per lo studio di trattamenti protettivi e consolidanti

Preliminary 1H NMR study on archaeological waterlogged wood.

Magnetic Resonance Relaxation (MRR) and Magnetic Resonance Imaging (MRI) are powerful tools to obtain detailed information on the pore space structure that one is unlikely to obtain in other ways. These techniques are particularly suitable for Cultural Heritage materials, because they use water 1H nuclei as a probe. Interaction with water is one of the main causes of deterioration of materials. Porous structure in wood, for example, favours the penetration of water, which can carry polluting substances and promote mould growth. A particular case is waterlogged wood from underwater discoveries and moist sites; in fact, these finds are very fragile because of chemical, physical and biological…