Figure F30. Axial field in two APC core barrels before demagnetization (filled squares), after demagnetization (diamonds), and after the demagnetized barrel completed a "round trip" to recover a core (open squares). Positive fields are downward relative to an upright core barrel and negative fields are upward (from Stokking et al., 1993).

Figure F30. Axial field in two APC core barrels before demagnetization (filled squares), after demagnetization (diamonds), and after the demagnetized barrel completed a "round trip" to recover a core (open squares). Positive fields are downward relative to an upright core barrel and negative fields are upward (from Stokking et al., 1993).