Section Aa

environments. Complete excitation coil and magnet assemblies are dropped several kilometres down bore holes in the search for oil by the petroleum industry. The sensitive volume is developed outside the sensor so that actual sampling of the liquid in the rock around the hole is possible.

A small transportable NMR system for control applications is now marketed by ATI Instruments. This system uses a condensed field magnet weighing only 45 kg, about 20% that of the equivalent electromagnet, and operates at the relatively high field strength of 1.4 T (60 MHz). It offers 1 cm sample diameter access. The applicability of this system has been demonstrated for applications in the food, petroleum, pulp and paper industries. However, most activity has concentrated on applications to polymers including additive concentrations, conversion rates, %polymer in recycled monomer and process stream composition. Snoddy (Snoddy, 1993) has used the spectrometer to determine the viscosity of polymer samples in a simulated production environment. The polymer viscosities were in the range 3300 to 5000 cP and the viscosity could be determined in less than 1 minute with a standard error of 112 cP.

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