Magnets for Small-Scale and Portable NMR

NMR magnets for portable applications using 3D printed materials

In this paper, we introduce 3D printing as a possibility for realizing lightweight, yet high-precision NMR magnets. Using a commercially available filament containing steel particles allows for the realization of critical components of NMR magnets such as pole pieces and even the flux-conducting yoke. In contrast to shimming structures made of iron, 3D printed structures made of the lightweight filament allow for a robust and inexpensive way of realizing high-performance NMR magnets for future portable NMR applications. We demonstrate the versatility and achievable high performance of the proposed solution with two different H-shaped NMR magnets. In the first magnet, the 3D-printed filament is used to realize the yoke that guides the magnetic flux inside the magnet, providing the potential for a substantial weight reduction compared to a conventional iron yoke. In the second magnet, we use the 3D-printed material to realize arbitrarily shaped passive shim structures. Numerical size and shape optimizations using non-uniform rational basis splines (NURBS) have been applied to obtain the optimal geometry. The two manufactured magnets achieve measured NMR spectral line widths of 54 ppm and 250 ppm, respectively. Our results clearly demonstrate the efficiency and versatility of the proposed design and optimization approach.

Low field, time domain NMR in the agriculture and agrifood sectors: An overview of applications in plants, foods and biofuels

In this contribution, a selective overview of low field, time-domain NMR (TD-NMR) applications in the agriculture and agrifood sectors is presented. The first applications of commercial TD-NMR instruments were in food and agriculture domains. Many of these earlier methods have now been recognized as standard methods by several international agencies. Since 2000, several new applications have been developed, using state of the art instruments, new pulse sequences and new signal processing methods. TD-NMR is expected, in the coming years, to become even more important in quality control of fresh food and agricultural products, as well as for a wide range of food-processed products. TD-NMR systems provide excellent means to collect data relevant for use in the agricultural environment and the bioenergy industry. Data and information collected by TD-NMR systems thus may support decision makers in business and public organizations.

Low-cost low-field NMR and MRI: Instrumentation and applications

While NMR and MRI are often thought of as expensive techniques requiring large institutional investment, opportunities for low-cost, low-field NMR and MRI abound. We discuss a number of approaches to performing magnetic resonance experiments with inexpensive, easy to find or build components, aimed at applications in industry, education, and research. Opportunities that aim to make NMR accessible to a broad community are highlighted. We describe and demonstrate some projects from our laboratory, including a new prototype instrument for measurements at frequencies up to ∼200 kHz and demonstrate its application to the study of the rapidly advancing technique known as inhomogeneous magnetization transfer imaging, a promising method for characterizing myelin in vivo.