Abstract: A solid ink jet ink composition which is suitable for hot melt applications having a carrier having an electrical resistivity of at least 10.sup.8 Ohm.cm, insoluble marking particles and a particle charging agent dispersed in it. The marking particle may be a pigment, an insoluble dyestuff, a polymer or mixture thereof. The particle charging agent may be a metal soap, a fatty acid, lecithin, an organic phosphorous compound, a succinimide, a sulphosuccinate, petroleum sulphonates, a soluble or partially soluble resin such as a modified rosin ester, an acrylic, a vinyl a hydrocarbon or a mixture thereof. The solid ink jet ink composition may further include a viscosity controller. The ink may be capable of being heated to 155.degree. C. and have at that temperature a viscosity of between 5 to 150 cps.

Abstract: A control method permits the operation of multiple superconducting magnetic coils so as to move a magnetic object to precisely specified locations within the body under command of a physician-operator observing the motion with live fluoroscopic imaging fused with more detailed preoperative imaging of some other kind. A computer contains the preoperative images and the fluoroscopic images, as well as the means to effect changes in the coil currents so as to accomplish the desired magnetic object motion and positioning. The control method operates the coils in pairs on opposite sides of the body in a manner to minimize the necessary current changes, thus avoiding the quenching of the superconducting coils. Combinations of these pairs can execute motion of the magnetic object in any direction in an impulsive manner and with high precision. The method should function well and provide advantages with coils which are not superconducting as well.