Seminar: "Measurements of dynamic properties with portable NMR: Sensitive volume as an integrator"

Dynamic properties are defined as a response of a sample to an applied dynamic stress. Changes in tissue viscoelasticity can be an indication of serious health issues; the flow induced in response to shear stress tells us if the fluid is Newtonian, or not.  The displacement caused by stress can be measured with various instrumentation.

Nuclear Magnetic Resonance (NMR) signal can be sensitized to measure displacements; its spatially-resolved NMR, also known as Magnetic Resonance Imaging (MRI), can provide a spatial distribution of stresses. However, conventional NMR and MRI instruments are big, expensive, and can only be used in a specially adapted laboratory. Portable NMR instruments, on the other hand, are small, portable, inexpensive, and can be used virtually anywhere. The NMR signal comes from a region called “sensitive volume” outside the magnet array, greatly expanding the range of potential applications for such instruments. They do have a more limited range of capabilities compared to conventional NMR/MRI so some novel approaches have to be developed.  

In my talk, I will discuss our recent progress, with a focus on how a well-controlled sensitive volume can be used as an integrator to measure dynamic properties. The examples will include: portable NMR measurements of viscoelasticity, flow index, transition to turbulence, and shear wave propagation. Future developments will be discussed.

Selby, W., Balcom, B.J., Newling, B., and Mastikhin, I. “Using phase interference to characterize dynamic properties – a review of constant gradient, portable magnetic resonance methods”. Front.Phys. (2023) 11, 1201032

Richard, S., Balcom, B.J., and Newling, B. "Determining the Flow Transition from Laminar to Turbulence Using Simple Spin-Echo Magnetic Resonance Techniques", Physics of Fluids (2023) 35(8), 084113

Selby, W., Garland, P., and Mastikhin, I. "A Simple Portable Magnetic Resonance Technique for Characterizing Circular Couette Flow of Non-Newtonian Fluids", Journal of Magnetic Resonance (2022) 345, 107325.

Selby, W., Garland, P., and Mastikhin, I. "Dynamic Mechanical Analysis with Portable NMR", Journal of Magnetic Resonance (2022) 339, 107211

Mastikhin, I., Barnhill, M., “Sensitization of a stray-field NMR to vibrations: a potential for MR elastometry with a portable NMR sensor”, Journal of Magnetic Resonance (2014) 248, 1-7

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