IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Internal Gradient Mapping with Distant Dipolar Field Contrast
Autor/es:
E.V. SILLETTA, M.B. FRANZONI, R.H. ACOSTA
Lugar:
Angra dos Reis, Río de Janeiro
Reunión:
Congreso; 13th NUCLEAR MAGNETIC RESONANCE USERS MEETING; 2011
Institución organizadora:
AUREMN
Resumen:
Porous media are systems widely encountered in nature and in technological applications. Typical examples are sandstones, catalysts, biological tissues, polymers and glass beads; they are generally important in industrial applications in various domains like oil production and pharmaceutical engineering. The existence of magnetic susceptibility differences between materials in the sample develops local magnetic field gradients at the interfaces when the sample is placed in a magnetic field. Such gradients are commonly referred to as “internal gradients” and are roughly expressed as g (proportional) (Delta Chi)*B0, where (Delta chi) is the magnetic susceptibility difference and B0 is the applied field [1]. Characterization of porous media from the structural and functional point of view often relies on NMR relaxation and diffusion measurements, nevertheless these measurements are greatly influenced by the presence of the internal gradients, hence their characterization is of utmost importance [2]. An alternative method to study porous media relies on the use of the Distant Dipolar Field (DDF), where intermolecular Multiple Quantum Coherences (iMQC) are converted into observable signal by intermolecular dipolar couplings. In this work we use DDF contrast to probe the internal gradients in a model system consisting of an arrange of capillaries doped with iron oxide.