... charging of powders J Electrostatics 1985, 16, 175–181 Pratt, T.H Electrostatic Ignitions of Fires and Explosions; Burgoyne: Marietta, GA, 1997, 115–152 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 ... exact value of the magnetic flux through the toroid cross section is Èexact "NIh ¼ 2% ðb dr "NIh b ¼ ln 2% a a r 3: 53 According to Eqs (3. 32) and (3. 33) , adopting the average length of the toroidal ... higher-field magnets (4 T) to help visualize the activity of the sensory, cognitive and motor system Figure 3. 24 shows an example of an MRI scan of the brain of one of Figure 3. 24 An MRI scan of...