scholarly journals Surface Nuclear Magnetic Resonance Monitoring Reveals Karst Unsaturated Zone Recharge Dynamics during a Rain Event

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3183
Author(s):  
Naomi Mazzilli ◽  
Konstantinos Chalikakis ◽  
Simon D. Carrière ◽  
Anatoly Legchenko
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Unsaturated Zone ◽  
Low Noise ◽  
Water Dynamics ◽  
Rain Event ◽  
Experimental Site ◽  
Initial State ◽  
Before And After ◽  
Nuclear Magnetic

Understanding karst unsaturated zone (UZ) recharge dynamics is crucial for achieving sustainable management of karst hydrosystems. In this paper, we provide the first report of the application of surface nuclear magnetic resonance (SNMR) monitoring of a karst UZ during a typical Mediterranean rain event. This 79 days’ SNMR monitoring is a part of a more than 2 years of SNMR monitoring at the Low Noise Underground Laboratory (LSBB) experimental site located within the Fontaine de Vaucluse karst hydrosystem (southeastern France). We present eight SNMR soundings conducted before and after the rain event that accumulated 168 mm in 5 days. The obtained results demonstrate the applicability and the efficiency of SNMR for investigating infiltration dynamics in karst UZs at the time scale of a few days. We present the SNMR amplitudes that highlight strong signal variations related to water dynamics in the karst UZ. Infiltrated water cause increased SNMR signal during 5 days after the rain event. A significant draining process of the medium starts 15 days after the main event. Finally, after 42 days, the SNMR signal returns close to the initial state.

Water dynamics in eggs by means of Nuclear Magnetic Resonance relaxometry

2021 ◽  
Vol 327 ◽  
pp. 106976
Author(s):  
Danuta Kruk ◽  
Małgorzata Florek-Wojciechowska ◽  
Mecit Oztop ◽  
Esmanur Ilhan ◽  
Zbigniew Wieczorek
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Dynamics ◽  
Nuclear Magnetic Resonance Relaxometry ◽  
Nuclear Magnetic

Influence of Freezing–Thawing Cycle on Water Dynamics of Turbot Flesh Assessed by Low-Field Nuclear Magnetic Resonance and Magnetic Resonance Imaging

2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Jiaqi Li ◽  
Kexin Xia ◽  
Yao Li ◽  
Mingqian Tan
Keyword(s):  
Magnetic Resonance Imaging ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Dynamics ◽  
Resonance Imaging ◽  
Low Field ◽  
Meat Spoilage ◽  
Thawing Process ◽  
Lf Nmr ◽  
Nuclear Magnetic

AbstractTurbot is a valuable commercial species due to its high nutrient content. Moisture is an important indicator of meat spoilage. This study elucidated distinctive water dynamics in turbot flesh in the freezing–thawing process by nondestructive low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) techniques.T2relaxation spectra were utilized to describe the mobility and content of different types of water. Principal component analysis (PCA) revealed a clear discrimination of various freezing–thawing cycles.T1- andT2-weighted MRI provided further visualization of internal information for turbot flesh. Microscopic examination clearly identified protein denaturation and structural shrinkage. Furthermore, NMR parameters and conventional physicochemical parameters of color, shear force and thiobarbituric acid-reactive substances showed good correlations. To sum up, the study revealed that LF-NMR and MRI are promising techniques to portray the relationship between the water dynamics and changes of turbot quality properties during the freezing–thawing process.

The high molecular weight polyphloroglucinols of the marine brown alga Fucusvesiculosus L. 1H and 13C nuclear magnetic resonance spectroscopy

1985 ◽  
Vol 63 (2) ◽  
pp. 304-313 ◽  
Author(s):  
A. Gavin McInnes ◽  
Mark A. Ragan ◽  
Donald G. Smith ◽  
John A. Walter
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
High Molecular Weight ◽  
Resonance Spectroscopy ◽  
13C Nuclear Magnetic Resonance ◽  
Before And After ◽  
Nuclear Magnetic

1H and 13C nuclear magnetic resonance spectroscopy of the high-molecular-weight (> 104) polyphenol fraction from Fucusvesiculosus, before and after acetylation or methylation, demonstrates that it is composed of phloroglucinol units (48.9 ± 3.5%) and 2,2′,4,4′,6,6′-hexahydroxybiphenyl, 2,2′,2″,4,4′,4″,6,6′,6″-nonahydroxy-1,1′:3′1″-terphenyl, and related quater-and polyphenyl groups (together, 51.1 ± 3.5%) linked by ether bonds, each bond involving the carbinol and methine carbons of different units and the formal loss of a molecule of hydrogen. The polymer is highly branched, with ca. 20 – 22% of the constituent units being chain termini; there is no evidence for large rings of units. Approximately 5 – 10% of the phloroglucinol and 54 – 82% of the directly bonded units occur on the exterior of the molecule, whereas the interior backbone consists predominantly of ether-linked phloroglucinol units.

Apsu — A new compact surface nuclear magnetic resonance system for groundwater investigation

Geophysics ◽  
2020 ◽  
Vol 85 (2) ◽  
pp. JM1-JM11 ◽  
Author(s):  
Jakob Juul Larsen ◽  
Lichao Liu ◽  
Denys Grombacher ◽  
Gordon Osterman ◽  
Esben Auken
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Larmor Frequency ◽  
Low Noise ◽  
Quality Data ◽  
Subsurface Water ◽  
Near Surface ◽  
Peak Current ◽  
Multiple Receivers ◽  
Nuclear Magnetic

Surface nuclear magnetic resonance (NMR) is emerging as a competitive method for aquifer exploration due to its direct sensitivity to subsurface water, but the method still has several shortcomings, for example, a signal-to-noise ratio that is often poor, long survey times, and bulky equipment. We have developed Apsu, a new surface NMR system designed for near-surface groundwater investigations. It provides several features such as a compact transmitter unit, separated, small receiver coils, wireless connections between multiple receivers, quasi-zero dead time, and robust phase determination. The transmitter unit is powered by a lightweight generator, and it drives a triangular current in an untuned [Formula: see text] transmitter coil. The peak current of the triangular waveform is up to 145 A, with an effective peak current of 105 A at a Larmor frequency of 2 kHz, corresponding to a 30 m depth of investigation. The frequency and amplitude in each half-oscillation of the transmit pulses can be modulated independently, which gives great flexibility in the pulse design. The receiver uses low-noise preamplifiers and multiple receivers linked to a central unit through Wi-Fi. The use of small receiver coils and wireless connections to multichannel receivers greatly improves the layout configuration flexibility and survey efficiency. The performance of the system under field conditions is demonstrated with high-quality data collected near Silkeborg, Denmark, using on-resonance and numerically optimized modulation pulses.

Water Dynamics of Mung bean (Vigna radiata) Sprouts Treated with 6-Benzylaminopurine: Discrimination by Low-Field Nuclear Magnetic Resonance and Spectrometry

2018 ◽  
Vol 14 (4) ◽  
Author(s):  
Zhuyi Lin ◽  
Ruiying Wang ◽  
Siqi Wang ◽  
Mingqian Tan
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mung Bean ◽  
Control Sample ◽  
Water Dynamics ◽  
Low Field ◽  
Significant Difference ◽  
Bean Sprouts ◽  
Lf Nmr ◽  
Nuclear Magnetic

AbstractMung bean sprouts are a kind of favorite healthy food across the world. As a forbidden plant hormone cytokinins, the use of 6-benzylaminopurine (6-BAP) in promoting the growth of bean sprouts is forbidden due to its safety concerns. Rapid analysis of 6-BAP treated bean sprouts is required to assess their growth changes and discriminate them from the normal sample. In this study, the water dynamics of growth for 6-BAP treated bean sprouts was monitored by the low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging. A simplified cartoon model of the water dynamics was proposed to explain the LF-NMR analysis result. Principal component analysis of the NMR relaxation data clearly showed the different water distribution of 6-BAP treated bean sprouts from the control sample. The juice of 6-BAP treated bean sprouts showed significant difference in the ultraviolet absorption and fluorescence spectra. Therefore, combining the spectrometry, the LF-NMR may have potential for rapid discrimination of the 6-BAP treated bean sprouts.

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