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Updated: Feb 25, 2026

Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
Dynamic viscoelasticity measurement under alternative torque using electromagnetically spinning method with quadruple
Yusuke Matsuura1, Taichi Hirano1, Keiji Sakai1
1Institute of Industrial Science, The University of Tokyo, Meguro, Tokyo 153-8505, Japan.
Abstract:
In this study, we developed a novel type of rheological measurement system. Here, a spherical probe is driven to rotate periodically by applying torques using quadruple electromagnets in a noncontact manner. Moreover, this system is an enhancement of our electromagnetically spinning (EMS) viscometer, which is widely used for measuring rheological flow curves in various industrial fields. The quadruple EMS method provides the frequency spectrum of viscoelasticity, in addition to shear viscosity, in a steady flow by switching the operation modes of the driving torque. We show the results obtained for Newtonian fluids and viscoelastic materials and demonstrate the validity of the system.
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