Читать книгу Essentials of MRI Safety - Donald W. McRobbie - Страница 80
Example 2.6 Force on a ferromagnetic object side on to B0
ОглавлениеIf the object in Example 2.5 has its long axis perpendicular to B0. What is the attractive force on it?
Firstly determine if the object is saturated. From Figure 2.14 or Equations A1.31 and 2.9b
In this orientation the object is not saturated so use Equation 2.11 with θ = 90°
(We could also have used Equation 2.13 using B = 0.1 T in place of Bsat).
This is one quarter of the gravitational force. The orientation of the object matters! Twisting it towards the magnet is potentially dangerous.