MAGNET CONSOLE DESIGN OF AN NMR-BASED SENSOR TO DETECT RIPENESS OF FRUIT

Abstract

ABSTRACT The use of nuclear magnetic resonance (NMR) principles is a possibility to nondestructively measure sugar (or sucrose) content in fruit. The magnet console for an NMR-based sensor to detect fruit ripeness (or sweetness) was designed through an interactive graphics simulation with a two-dimensional finite element model (FEM). A permanent magnet was used as the magnetic source because of its lower cost. The simulated finite element magnetic fields were verified by comparison with magnetic fields measured in an experimental magnet console. The agreement between predictions and measurements was good with an error of 4.7%. Pole surface plates and shimming frames were used to improve the homogeneity of the magnetic fields around the air gap center where the fruit would be located.system performed reliably at a sustained harvesting rate of approximately 1.4 ha/day (3.4 acre/day), while indicating that a rate of 2 ha/day (5 acre/day) should be easily achievable. The system is operated by two workers and reduces conventional labor requirement by approximately 80-85%.