Magnetic resonance in porous media: Recent progress

Abstract

The anomalous adsorbate dynamics at surfaces in porous media studied by nuclear magnetic resonance methods. The orientational structure factor and Lévy walks J. Chem. Phys. 109, 6929 (1998) Recent years have seen significant progress in the NMR study of porous media from natural and industrial sources and of cultural significance such as paintings. This paper provides a brief outline of the recent technical development of NMR in this area. These advances are relevant for broad NMR applications in material characterization.

Detecting diffusion-diffraction patterns in size distribution phantoms using double-pulsed field gradient NMR: Theory and experiments

“…Techniques often used such as diffusion tensor imaging 9 can characterize the anisotropy present when pores are coherently placed within the specimen, 10 while multiple diffusion time experiments can, to a certain extent, characterize the tortuosity and surface to volume ratio 5,11,12 and fractal dimensions 13 of the specimen. Other diffusionbased methods exist to quantify flow phenomena, [14][15][16][17] the internal magnetic field of the samples, [18][19][20] and to a certain extent, exchange properties 21,22 of the porous media.…”

Modeling 1H NMR transverse magnetization decay in polysiloxane-silica composites

“…The expressions investigated above all produce similar results for the RDC strength and radiation effects thereof in PDMS-based materials. These close-formed expressions, particularly that based on the use of the second moment approximation, portend simple extraction of parameters without the use of regularization techniques or numerical inverse Laplace transformations (Song et al, 2008). Coupling these results with those established previously provides a simple yet powerful way for determining and imaging (Mayer et al, 2007) subtle, spatially heterogenous changes in soft materials due to the wide range of harsh chemical, physical, mechanical, and radiological environments that ultimately limit useful device lifetimes through irreversible changes in constituent components.…”

Unilateral NMR investigation of multifunctional treatments on stones based on colloidal inorganic and organic nanoparticles

“…[49,50] In SGSTE, the attenuation of the spin echo signal, which results from the dephasing of nuclear spins, is used to measure molecular displacement. The normalized signal attenuation is affected by both longitudinal and transverse relaxation processes and by translational motion of spins and is given by the following equation: [51] ln…”