Electromagnetic Design and Mechanical Behavior Analysis of an 850 MHz All REBCO Nuclear Magnetic Resonance Magnet

Li, Da; Wang, Hongzhi; Ren, Yong; Wang, Dongquan

doi:10.1109/tasc.2021.3052825

Cited by 7 publications

(4 citation statements)

References 40 publications

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“…For instance, multi-direction pulling forces may be strong enough that an openable mechanical structure could not be released easily during a test cycle. Thus, it is essential to provide an appropriate design to lessen consequences of the existing pulling force in the NMR ( Li et al., 2021 ). The mechanical structure should be in a way that the Halbach rings can be opened with minimal forces required, which can be simulated using finite element analysis tools.…”

Section: Challenges In Designing Portable Nmr For Sap Flow Measurementmentioning

confidence: 99%

Challenges and advances in measuring sap flow in agriculture and agroforestry: A review with focus on nuclear magnetic resonance

Kumar

Hosseinzadehtaher²,

Hein³

et al. 2022

Front. Plant Sci.

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Sap flow measurement is one of the most effective methods for quantifying plant water use.A better understanding of sap flow dynamics can aid in more efficient water and crop management, particularly under unpredictable rainfall patterns and water scarcity resulting from climate change. In addition to detecting infected plants, sap flow measurement helps select plant species that could better cope with hotter and drier conditions. There exist multiple methods to measure sap flow including heat balance, dyes and radiolabeled tracers. Heat sensor-based techniques are the most popular and commercially available to study plant hydraulics, even though most of them are invasive and associated with multiple kinds of errors. Heat-based methods are prone to errors due to misalignment of probes and wounding, despite all the advances in this technology. Among existing methods for measuring sap flow, nuclear magnetic resonance (NMR) is an appropriate non-invasive approach. However, there are challenges associated with applications of NMR to measure sap flow in trees or field crops, such as producing homogeneous magnetic field, bulkiness and poor portable nature of the instruments, and operational complexity. Nonetheless, various advances have been recently made that allow the manufacture of portable NMR tools for measuring sap flow in plants. The basic concept of the portal NMR tool is based on an external magnetic field to measure the sap flow and hence advances in magnet types and magnet arrangements (e.g., C-type, U-type, and Halbach magnets) are critical components of NMR-based sap flow measuring tools. Developing a non-invasive, portable and inexpensive NMR tool that can be easily used under field conditions would significantly improve our ability to monitor vegetation responses to environmental change.

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Section: Challenges In Designing Portable Nmr For Sap Flow Measurementmentioning

confidence: 99%

Challenges and advances in measuring sap flow in agriculture and agroforestry: A review with focus on nuclear magnetic resonance

Kumar

Hosseinzadehtaher²,

Hein³

et al. 2022

Front. Plant Sci.

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show abstract

“…Furthermore, it should be noted that extreme amounts of pulling forces might gradually misalign the NMR mechanical structure and degrade the homogeneity of the magnetic field in the RoT. Therefore, it is necessary to provide an applicable design to reduce the pulling forces among the magnets [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

On Design Challenges of Portable Nuclear Magnetic Resonance System

Hosseinzadehtaher

D’silva

Baker

et al. 2023

JNE

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This article studies the optimal design approach for a portable nuclear magnetic resonance (NMR) system for use in non-destructive flow measurement applications. The mechanical and electromagnetic design procedures were carried out using the Ansys Maxwell finite-element analysis (FEA) software tool. The proposed procedure considered homogeneity and strength constraints while ensuring the desired functionality of the intended device for a given application. A modified particle swarm optimization (MPSO) algorithm was proposed as a reference design framework for optimization stages. The optimally designed NMR tool was prototyped, and its functionality was validated via several case studies. To assess the functionality of the prototyped device, Larmor frequency for hydrogen atom was captured and compared with theoretical results. Furthermore, the functionality and accuracy of the prototyped NMR tool is compared to the off-the-shelf NMR tool. Results demonstrated the feasibility and accuracy of the prototyped NMR tool constrained by factors, such as being lightweight and compact.

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“…Among the techniques available for the measurement of sap flow, nuclear magnetic resonance (NMR) is an appropriate non-invasive method [7,20]. However, the currently available NMR equipment is limited by bulkiness [21,22], operational complexity, poor instrument portability [23,24], and complex procedures and data processing techniques, and it is expensive [7,22,25]. Therefore, it is hard to use measurement tools to assess sap flow to satisfy the demands of the automatic prediction of tree transpiration.…”

Section: Introductionmentioning

confidence: 99%

An Improved Sap Flow Prediction Model Based on CNN-GRU-BiLSTM and Factor Analysis of Historical Environmental Variables

Guo

Wang

et al. 2023

Forests

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Sap flow is widely used to estimate the transpiration and water consumption of canopies and to manage water resources. In this paper, an improved time series prediction model was proposed by integrating three basic networks—CNN, GRU and BiLSTM—to assess sap flow with historical environment variables. A dataset with 17,569 records of each, including 9 environment variables and 1 sap flow, was applied from a public database of SAPFLUXNET. After normalization, the environment variables were analyzed and composed with the factor analysis method. After the CNN-GRU-BiLSTM structure was designed, N records of three main factors were computed from environment variables, which were measured at N previous moments, and the sap flow was measured at the current moment, and they were applied for each training, validation, and testing cycle. To improve and compare the CNN-GRU-BiLSTM-based model, nine other models, using the methods of multiple linear regression, support vector regression, random forest, LSTM, GRU, BiLSTM, CNN-GRU, CNN-BiLSTM, and CNN-GRU-LSTM, were constructed in this study, respectively. Results show that the performance of the CNN-GRU-BiLSTM-based model has more accuracy than the other nine models we built in this paper, with the mean absolute error, mean squared error, mean absolute percentage error, and coefficient of determination (R2) being 0.0410, 0.0029, 0.2708 and 0.9329, respectively. Furthermore, for a comparison of the descending dimension method of factor analysis, principal component analysis (PCA) and singular value decomposition (SVD) methods were applied and compared, respectively. Results show that the performance of the factor analysis-based model is better than the PCA- or SVD-based model, with the R2 results of the factor analysis-based model being higher than the PCA- and SVD-based models by 5.06% and 10.63%, respectively. This study indicates that the CNN-GRU-BiLSTM-based sap flow prediction model established with a factor analysis of historical environmental variables has optimistic applications for analyzing the transpiration of trees and evaluating water consumption.

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Electromagnetic Design and Mechanical Behavior Analysis of an 850 MHz All REBCO Nuclear Magnetic Resonance Magnet

Cited by 7 publications

References 40 publications

Challenges and advances in measuring sap flow in agriculture and agroforestry: A review with focus on nuclear magnetic resonance

Challenges and advances in measuring sap flow in agriculture and agroforestry: A review with focus on nuclear magnetic resonance

On Design Challenges of Portable Nuclear Magnetic Resonance System

An Improved Sap Flow Prediction Model Based on CNN-GRU-BiLSTM and Factor Analysis of Historical Environmental Variables

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