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Scientists at IIT Patna have developed a hybrid magneto-rheometer to advance research on magnetorheological (MR) fluids.
The instrument generates a constant, high-strength magnetic field across an MR fluid sample while drawing comparatively low electrical current.
It measures rheological behaviour — flow and deformation — and tribological behaviour — friction and wear — simultaneously, under compression and shear.
The team prepared nano iron powder-based MR fluids and tested them with and without a magnetic field.
The research was published in the journal Rheologica Acta.
An MR fluid is a suspension of microscopic magnetisable particles, usually iron, in a carrier oil. Without a magnetic field it flows like any thick liquid. Apply a field and the particles align into chains along the field lines within milliseconds, and the fluid stiffens until it behaves almost like a solid; remove the field and it flows again. Because the stiffness can be tuned continuously by varying the current, MR fluids are used wherever a damper or brake must adapt in real time — adaptive vehicle suspensions that stiffen over rough ground, prosthetic knees that adjust resistance to a wearer's gait, clutches and brakes, and seismic dampers in buildings. The class of materials was first demonstrated by Jacob Rabinow in the late 1940s. The engineering difficulty has always been measurement: the fluid's useful properties only appear inside a magnetic field, so any instrument must impose a strong, uniform field while simultaneously measuring how the fluid flows and wears.
Simple Analogy: It is a liquid with a switch. Current on, and it thickens towards a solid; current off, and it pours again — and the switch has a dial, not just two positions.
General Awareness > Science and technology developments in India
GS Paper III > Science and technology, developments and applications in everyday life
General Awareness > General science
A suspension of magnetisable particles in a carrier liquid whose viscosity rises sharply when a magnetic field is applied.
The study of the flow and deformation of matter.
The study of friction, wear and lubrication between interacting surfaces.
Two modes of loading a material — sliding layers past one another, and pressing them together.
A material whose properties can be changed in a controlled way by an external stimulus such as a magnetic or electric field.