scholarly journals MR Study of Water Distribution in a Beech (Fagus sylvatica) Branch Using Relaxometry Methods

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4305
Author(s):  
Urša Mikac ◽  
Maks Merela ◽  
Primož Oven ◽  
Ana Sepe ◽  
Igor Serša
Keyword(s):  
Water Distribution ◽  
Relaxation Times ◽  
Physical And Mechanical Properties ◽  
Efficient Tool ◽  
Environmentally Sustainable ◽  
Nmr Relaxometry ◽  
Water State ◽  
State Of Water ◽  
Hygroscopic Nature ◽  
Beech Sample

Wood is a widely used material because it is environmentally sustainable, renewable and relatively inexpensive. Due to the hygroscopic nature of wood, its physical and mechanical properties as well as the susceptibility to fungal decay are strongly influenced by its moisture content, constantly changing in the course of everyday use. Therefore, the understanding of the water state (free or bound) and its distribution at different moisture contents is of great importance. In this study, changes of the water state and its distribution in a beech sample while drying from the green (fresh cut) to the absolutely dry state were monitored by 1D and 2D 1H NMR relaxometry as well as by spatial mapping of the relaxation times T1 and T2. The relaxometry results are consistent with the model of homogeneously emptying pores in the bioporous system with connected pores. This was also confirmed by the relaxation time mapping results which revealed the moisture transport in the course of drying from an axially oriented early- and latewood system to radial rays through which it evaporates from the branch. The results of this study confirmed that MRI is an efficient tool to study the pathways of water transport in wood in the course of drying and is capable of determining the state of water and its distribution in wood.

scholarly journals Appraisal of water quality indices for service reservoirs in water distribution networks

2020 ◽  
Vol 81 (8) ◽  
pp. 1606-1614 ◽  
Author(s):  
M. S. Nyirenda ◽  
T. T. Tanyimboh
Keyword(s):  
Water Quality ◽  
Water Distribution ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Sampling Point ◽  
Quality Indices ◽  
Water Quality Indices ◽  
State Of Water ◽  
Pollution Loads

Abstract The use of water quality indices to aggregate pollution loads in rivers has been widely studied, with researchers using various sub-indices and aggregation methods. These have been used to combine various quality variables at a sampling point in a river into an overall water quality index to compare the state of water quality in different river reaches. Service reservoirs in a water distribution network, like rivers, have complex mixing mechanisms, are subjected to various water quality variables and are variably sized and sited. Water quality indices and the relevant sub-indices are formulated here and applied to service reservoirs within a water distribution network. This is in an attempt to compare holistically the performance of service reservoirs in solutions of optimisation algorithms with regards to water quality.

Estimating the NMR surface relaxivity of Eocene sandstones: a comparison of different approaches

Geophysics ◽  
2020 ◽  
pp. 1-44
Author(s):  
Zeyu Zhang ◽  
Andreas Weller
Keyword(s):  
Relaxation Time ◽  
Pore Radius ◽  
Gas Adsorption ◽  
Fractal Theory ◽  
Relaxation Times ◽  
Adsorption Method ◽  
Throat Radius ◽  
Reliable Determination ◽  
Surface Relaxivity ◽  
Nmr Relaxometry

Nuclear magnetic resonance (NMR) relaxometry typically involves the analysis of a relaxation time distribution. The surface relaxivity ( ρ) is the key parameter that relates the relaxation time to the pore radius. Only a good estimate of the surface relaxivity enables a reliable determination of the pore radius distribution in a rock or sediment sample. A wide variety of approaches for the estimation of ρ has been proposed; however, the accuracy of ρ determination approaches has rarely been checked. We have compared different approaches of ρ determination for a set of Eocene sandstone samples. Most approaches based on a weighted logarithmic mean of relaxation times or the peak relaxation time result in significant underestimation of ρ. However, the correct weighting of the set of relaxation times proved to be a crucial approach in ρ determination. The consequent application of geometric rules suggests the application of the weighted harmonic mean ( Thm). The specific surface area per unit pore volume ( Spor), which results from the gas adsorption method, is another crucial parameter in most approaches for ρ estimation. The quantities Thm and Spor depend on the resolution of the used method. Applying the fractal theory, we adopt an approach that performs an upscaling of Spor to the resolution of the NMR relaxometry. Using equal resolution for Thm and Spor, we obtain more reliable ρ estimates. The resulting ρ values are comparable with the ones determined by using the median relaxation time from NMR and the median pore-throat radius from the mercury injection capillary pressure method.

The state of water in thermoresponsive poly(acryloyl-l-proline methyl ester) hydrogels observed by DSC and 1H-NMR relaxometry

1999 ◽  
Vol 55 (2) ◽  
pp. 209-218 ◽  
Author(s):  
Mario Carenza ◽  
Gianna Cojazzi ◽  
Barbara Bracci ◽  
Laura Lendinara ◽  
Lina Vitali ◽  
...  
Keyword(s):  
Methyl Ester ◽  
1H Nmr ◽  
The State ◽  
Nmr Relaxometry ◽  
State Of Water ◽  
1H Nmr Relaxometry

scholarly journals NMR relaxometry: Spin lattice relaxation times in the laboratory frame versus spin lattice relaxation times in the rotating frame

2010 ◽  
Vol 495 (4-6) ◽  
pp. 287-291 ◽  
Author(s):  
Emilie Steiner ◽  
Mehdi Yemloul ◽  
Laouès Guendouz ◽  
Sébastien Leclerc ◽  
Anthony Robert ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Lattice Relaxation ◽  
Laboratory Frame ◽  
Spin Lattice Relaxation ◽  
Rotating Frame ◽  
Spin Lattice ◽  
Nmr Relaxometry

Molecular Dynamics of Monomer, Oligomer, and Polymer Liquids in Porous Media: A Field-Cycling Nmr Relaxometry and NMR Field-Gradient Diffusometry Study

1994 ◽  
Vol 366 ◽  
Author(s):  
R. Kimmich ◽  
S. Stapf ◽  
R.-O. Seitter ◽  
P. Callaghan ◽  
E. Khozina
Keyword(s):  
Molecular Dynamics ◽  
Porous Media ◽  
Field Gradient ◽  
Relaxation Times ◽  
Lattice Relaxation ◽  
Porous Matrix ◽  
Spin Lattice Relaxation ◽  
Nmr Relaxometry ◽  
Lévy Walks ◽  
Field Cycling

ABSTRACTThe molecular dynamics of fluids in porous media has been studied using field-cycling NMR relaxometry and NMR field-gradient diffusometry. The frequency dependences of the 1H and 2H spin-lattice relaxation times T1 of various liquids in porous glass reveal weak and strong adsorption behaviour depending on the polarity of the adsorbates. Correlation times eight orders of magnitude longer than in bulk have been observed. The T1 dispersion moreover reflects geometrical details of the matrix in a length scale three orders of magnitude longer than the adsorbate molecules. The mean-square displacements of adsorbate molecules on the surface are only one order of magnitude less than in bulk. The global diffusivity is reduced by tortuosity and porosity effects. The observed phenomena may be explained by bulk-mediated surface diffusion, i.e., Lévy walks. The dynamics of polymer chains much longer than the pore size is characteristicly different from that in bulk melts. There is evidence that the reptation mechanism explains at least a part of the phenomena observed for the porous matrix in contrast to findings with bulk polymer melts.

scholarly journals Nuclear Magnetic Resonance with Fast Field-Cycling Setup: A Valid Tool for Soil Quality Investigation

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1040 ◽  
Author(s):  
Pellegrino Conte ◽  
Paolo Lo Meo
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nutrient Dynamics ◽  
Relaxation Times ◽  
Liquid Mixtures ◽  
Soil Science ◽  
Nmr Relaxometry ◽  
Field Cycling ◽  
Fast Field ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) techniques are largely employed in several fields. As an example, NMR spectroscopy is used to provide structural and conformational information on pure systems, while affording quantitative evaluation on the number of nuclei in a given chemical environment. When dealing with relaxation, NMR allows understanding of molecular dynamics, i.e., the time evolution of molecular motions. The analysis of relaxation times conducted on complex liquid–liquid and solid–liquid mixtures is directly related to the nature of the interactions among the components of the mixture. In the present review paper, the peculiarities of low resolution fast field-cycling (FFC) NMR relaxometry in soil science are reported. In particular, the general aspects of the typical FFC NMR relaxometry experiment are firstly provided. Afterwards, a discussion on the main mathematical models to be used to “read” and interpret experimental data on soils is given. Following this, an overview on the main results in soil science is supplied. Finally, new FFC NMR-based hypotheses on nutrient dynamics in soils are described

scholarly journals Research on the drying Mechanism of Astragali Radix during Processing

2021 ◽  
Author(s):  
Jie Peng ◽  
Meng-Mei Wu ◽  
Li-Fang Ye ◽  
Meng-Hua Wu ◽  
Zhi-Guo Ma ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Moisture Content ◽  
Water Distribution ◽  
Water Status ◽  
Relaxation Times ◽  
Scientific Basis ◽  
Drying Process ◽  
Texture Analyzer ◽  
Water Signal ◽  
Lf Nmr

Abstract Backgroundstragali Radix (Huangqi) is an important Chinese herbal medicine that is always processed into pieces for clinical use. There are many operations required after harvesting, among which drying of AR pieces is a key step. Unfortunately, research on the drying mechanism is still limited.MethodsLow-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) techniques were applied to study the water status and water distribution during the drying process. The contents of bioactive ingredients and texture changes were measured by HPLC and texture analyzer, respectively.ResultsDuring the drying process, the moisture content first decreased rapidly. After a particular time, the moisture content decreased slowly, and the equilibrium value was reached. The trends for changes in flavonoid glycoside and flavonoid aglycone contents in AR pieces were entirely opposite. The relaxation times T22 and T23 and the peak areas A22 and ATotal decreased significantly during drying. In addition, the intensity of the water signal decreased from the surface to the interior. The textural parameters hardness, adhesion and fracturability increased without an apparent change in springiness. The parameters of LF-NMR and the texture analyzer were correlated with water content.ConclusionsThis study indicated that HPLC, LF-NMR, MRI and texture analyzers provide a scientific basis for elucidating the principles for drying of AR pieces. The method is useful and shows potential for popularization and application; accordingly, it can easily be extended to other radix and/or rhizoma Traditional Chinese Medicinal materials.

scholarly journals A new method of determining the state of water and agricultural areas in real time

2019 ◽  
Vol 75 (2) ◽  
pp. 28-35 ◽  
Author(s):  
Nikita Sergeevich Myazin ◽  
Vadim Vladimirovich Davydov ◽  
Victoria Valerevna Yushkova ◽  
Vasiliy Yurevich Rud'
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic System ◽  
Relaxation Times ◽  
Signal Spectrum ◽  
Technical Solution ◽  
Environmental Condition ◽  
Transverse Relaxation ◽  
State Of Water ◽  
Laboratory Results ◽  
Agricultural Areas

Paper discusses the technique of environmental condition monitoring based on the phenomenon of nuclear magnetic resonance (NMR). Express control is an integral part of agriculture, because when working on farms or in fields there are situations when it is physically impossible to deliver samples for research to a stationary laboratory (results are needed urgently or samples can change their properties during transportation). A brief review of the existing methods for monitoring the states of media in the express mode was carried out, their shortcomings were revealed and a new technical solution to this problem was proposed. For a small-sized NMR spectrometer, a new magnetic system and a signal registration circuit have been developed, which makes it possible to detect the NMR signal at different frequencies, thus registering the signal spectrum. In addition, this design also allows measuring the longitudinal and transverse relaxation times of the medium. With the help of the proposed technique, studies of various media have been carried out; the results of these studies are presented.

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