Sensitization of a stray-field NMR to vibrations: A potential for MR elastometry with a portable NMR sensor

Mastikhin, Igor V.; Barnhill, Marie

doi:10.1016/j.jmr.2014.09.003

Cited by 3 publications

(6 citation statements)

References 32 publications

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“…First, we will outline general theoretical concepts that are fundamental to the MR signal analysis in all experiments. We will establish the versatility of phase interference-based methods by expanding the general analysis into more specific applications such as longitudinal and shear wave elastometry [33,34], and laminar pipe and Couette flow of non-Newtonian fluids [35,36].…”

Section: Open Access Edited Bymentioning

confidence: 99%

“…In the case of constant gradient portable MR, refocusing pulses results in an effective gradient in the form of a square wave; hence, the coefficient of 1 2 is replaced by 2 π [33]. Given the finite dimensions of the MR sensor, the distribution of velocities resulting from the propagating shear wave leads to phase interference that depends on the ratio between the wavelength and sensor size.…”

Section: Signal Analysis For Shear Stressmentioning

confidence: 99%

“…Consider a simple approximation, a 1D sensitive region, through which the shear wave propagates in the z-direction, with particle displacements in the direction of the gradient (x). If the sensor size covers a complete wavelength, there exists a closed-form analytical solution for the MR signal [33],…”

Section: Signal Analysis For Shear Stressmentioning

confidence: 99%

“…In shear and longitudinal wave experiments, a dual-channel signal generator was used to synchronize the MR acquisition with mechanical vibrations [33,34]. The first channel sent a signal to a mechanical actuator.…”

Section: Inducing Motion 421 Elastometrymentioning

confidence: 99%

“…Cylindrical (16 mm thick, 76 mm diameter) polyurethane and square (50 mm × 50 mm × 6 mm) Sorbothane samples were analyzed in shear wave experiments [33]. CPMG echo trains with 16 echoes were acquired with echo times corresponding to half the periods of mechanical vibrations at amplitudes of 0.152, 0.38, 0.48, 0.71, 0.86, 1.01, 1.2, and 1.35 μm.…”

Section: Shear Wave Elastometrymentioning

confidence: 99%

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Using phase interference to characterize dynamic properties—a review of constant gradient, portable magnetic resonance methods

et al. 2023

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Spatially resolved motion-sensitized magnetic resonance (MR) is a powerful tool for studying the dynamic properties of materials. Traditional methods involve using large, expensive equipment to create images of sample displacement by measuring the spatially resolved MR signal response to time-varying magnetic field gradients. In these systems, both the sample and the stress applicator are typically positioned inside a magnet bore. Portable MR instruments with constant gradients are more accessible, with fewer limitations on sample size, and they can be used in industrial settings to study samples under deformation or flow. We propose a view in which the well-controlled sensitive region of a magnet array acts as an integrator, with the velocity distribution leading to phase interference in the detected signal, which encodes information on the sample’s dynamic properties. For example, in laminar flows of Newtonian and non-Newtonian fluids, the velocity distribution can be determined analytically and used to extract the fluid’s dynamic properties from the MR signal magnitude and/or phase. This review covers general procedures, practical considerations, and examples of applications in dynamic mechanical analysis and fluid rheology (viscoelastic deformation, laminar pipe flows, and Couette flows). Given that these techniques are relatively uncommon in the broader magnetic resonance community, this review is intended for both advanced NMR users and a more general physics/engineering audience interested in rheological applications of NMR.

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