scholarly journals Improving the Hydrogeologic Conceptualization of a Remote Semi-Arid Palaeovalley Groundwater System using Airborne Electromagnetics, Seismic Refraction and Reflection, and Downhole Nuclear Magnetic Resonance

Geophysics ◽  
2021 ◽  
pp. 1-76
Author(s):  
Brady Flinchum ◽  
Luk Peeters ◽  
Tim Munday ◽  
Kevin Cahill
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Groundwater Resources ◽  
Seismic Refraction ◽  
Main Trunk ◽  
Groundwater System ◽  
Elastic Data ◽  
The Difference ◽  
Bedrock Aquifers ◽  
Nuclear Magnetic

A hydrogeologic conceptualization is critical to understand, manage, protect, and sustain groundwater resources, especially in regions where data are sparse, and accessibility is difficult. We used airborne electromagnetic (AEM), shallow seismic reflection and refraction data, and downhole nuclear magnetic resonance (NMR) logs to improve our understanding of an arid groundwater system influenced by palaeovalleys. In the current hydrogeologic conceptualization it is unknown if the palaeovalley and underlying bedrock aquifers are connected. We focused on defining the spatial distribution of saprolite, which is the layer of chemically altered rock separating the palaeovalley and bedrock aquifers. The AEM data provided an estimate of the top of saprolite but failed to effectively image the bottom. In contrast, the seismic data provided an estimate of the bottom of saprolite but failed to image the top. This unique geophysical combination of electrical and elastic data allowed us to map saprolite thickness in detail along a 1.7 km long transect that runs perpendicular the main trunk of a well-defined palaeovalley. We show that the palaeovalley is lined with a heterogenous layer of saprolite (3-120 m thick) that is thickest near the palaeovalley edges. Despite the variability, only a small percentage of the bedrock aquifer (8-17%) is in contact with the palaeovalley aquifer. Furthermore, the lack of an elastic boundary at the top of saprolite suggests that the porosity of the saprolite is similar to the palaeovalley sediments. An observation that is supported by the downhole NMR water contents. The electrical change at the top of saprolite is caused by a change in pore structure associated with the difference of weathering in situ versus transported materials. Our geophysical data suggest that the saprolite acts as an aquitard limiting groundwater exchange between the palaeovalley and bedrock aquifers.

Relationships between the proton nuclear magnetic resonance properties of plasma lipoproteins and cancer

1991 ◽  
Vol 37 (3) ◽  
pp. 369-376 ◽  
Author(s):  
J D Otvos ◽  
E J Jeyarajah ◽  
L W Hayes ◽  
D S Freedman ◽  
N A Janjan ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Plasma Lipids ◽  
Plasma Lipoproteins ◽  
Proton Nuclear Magnetic Resonance ◽  
High Density Lipoproteins ◽  
Cancer Group ◽  
Lipoprotein Lipid ◽  
The Difference ◽  
Nuclear Magnetic

Abstract We conducted a comprehensive investigation of the origin of nuclear magnetic resonance (NMR) lineshape variability of plasma lipids among healthy individuals and those with cancer. The methyl and methylene resonances of lipid in human plasma, whose linewidths have been reported to correlate with the presence of malignancy, are composed of the overlapping resonances of "mobile" protons from the major lipoproteins (very-low-, low-, and high-density lipoproteins). We tested two hypotheses for the origin of the narrower plasma linewidths observed for cancer patients: (a) malignancy-associated differences in the spectral properties (chemical shift, lineshape) of one or more of the lipoproteins, and (b) differences in the fraction of lipoprotein lipid giving rise to detectable NMR signal. Analysis of the concentrations of lipoprotein lipid and of 500 MHz NMR spectra of the lipoprotein constituents in greater than 100 plasma samples failed to provide support for either hypothesis. Although linewidths were found to be significantly narrower for the cancer group, the difference is entirely attributable to differences in the concentrations of the lipoproteins.

Synthesis and nuclear magnetic resonance spectra of some partially acylated β-D-glucopyranosides

1968 ◽  
Vol 46 (15) ◽  
pp. 2485-2493 ◽  
Author(s):  
A. P. Tulloch ◽  
A. Hill
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Trimethylsilyl Ether ◽  
Ether Group ◽  
Nuclear Magnetic Resonance Spectra ◽  
The Difference ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The synthesis of ten new partially acylated derivatives of methyl β-D-glucopyranoside, all with an acyl group at C-6, is described. The nuclear magnetic resonance spectra of these compounds, and of a number of related derivatives, have been measured using pyridine, acetone-d6, and deuteriochloroform as solvents. When OH-4 is acylated, the H-6 signals are at higher field (by 0.1–0.3 p.p.m.) than when OH-4 is not acylated, but this effect is not observed when OH-3 is acylated. When a trimethylsilyl ether group is introduced at C-4 the difference between the chemical shifts of the H-6 protons (δA –δB) increases markedly. Estimation of JBX and JAX (where B is the H-6 proton at higher field and X is H-5), from spectra obtained using acetone-d6 and pyridine as solvents, shows that JBX < JAX when there is an acyl group at C-4 but JBX > JAX when there is no acyl group at C-4.

Conformation of the C15 lupine alkaloids

1967 ◽  
Vol 45 (13) ◽  
pp. 1447-1457 ◽  
Author(s):  
M Wiewiorowski ◽  
O E Edwards ◽  
M D Bratek-Wiewiorowska
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mercuric Acetate ◽  
Lone Pair ◽  
Chair Conformation ◽  
Boat Conformation ◽  
Acid Complex ◽  
Nuclear Magnetic Resonance Spectra ◽  
The Difference ◽  
Nuclear Magnetic

Methods have been developed for preparing 17α-deuterio-, 17β-deuterio-, and l7-dideuteriolupanines. The nuclear magnetic resonance and infrared spectra of these provided strong evidence that ring C in the alkaloid is in a boat conformation in solution. Reduction of these compounds to the deuterated sparteines confirmed the same geometry for sparteine. In contrast, moilodeuteration of aphylline at C-17 showed that i t had an all-chair conformation in solution. 13β-Hydroxylupanine was shown to have the same conformation as lupanine in solution, but to adopt an all-chair conformation in the solid state. Interpretation of the nuclear magnetic resonance spectra enabled the conformation of ring C of 15-oxosparteine to be assigned. The oxidation and reductions involving C-17 of lupanine have been shown to be highly stereospecific, and an interpretation is given of the difference betmeen the dehydrogenation of lupanine by mercuric acetate and those by Nbromosuccinimide or by the mercuric acetate - ethylenediatninetetraacetic acid complex. It has now been found that the C—H stretching “trans bands” in the infrared are evident when only one hydrogen is alpha to the basic nitrogen and in an antiparallel relation to the lone pair of electrons.

Nuclear Magnetic Resonance Studies on Microstructure of Cement Pastes

2010 ◽  
Vol 177 ◽  
pp. 518-521 ◽  
Author(s):  
Dan Jin ◽  
Wu Yao ◽  
An Ming She ◽  
Xiao Yan Liu
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Fast Diffusion ◽  
Cement Pastes ◽  
Bulk Fluid ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
The Difference ◽  
Nuclear Magnetic

For water filled porous materials, the difference between the relaxation time of molecules at the pore surface and the relaxation time of molecules in the bulk fluid can be interpreted by a fast diffusion model. With this model, the nuclear magnetic resonance (NMR) can be applied to investigate the microstructure of cement pastes. The cement pastes we tested are two series, one is of same water to cement ratio (w/c=0.4) at different curing time (7d, 28d and 90d), the other is of different water to cement ratio (w/c=0.3, 0.4 and0.5, respectively) at the same curing day. Comparing results by NMR method with those by mercury intrusion porosimetry (MIP) shows that NMR is a convenient and nondestructive way to probe pore distribution of cement pastes.

The difference between protein structures obtained by x-ray analysis and nuclear magnetic resonance

2005 ◽  
Vol 39 (1) ◽  
pp. 113-122 ◽  
Author(s):  
B. S. Melnik ◽  
S. O. Garbuzynskiy ◽  
M. Yu. Lobanov ◽  
O. V. Galzitskaya
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Protein Structures ◽  
X Ray ◽  
The Difference ◽  
Nuclear Magnetic

Application of Low-Field Nuclear Magnetic Resonance (LFNMR) in Characterizing Coal Pores and Permeability

2013 ◽  
Vol 718-720 ◽  
pp. 1012-1017 ◽  
Author(s):  
Jun Gang Liu ◽  
Da Meng Liu ◽  
Yan Bin Yao ◽  
Jian Guo Wu ◽  
Jun Qian Li
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Coal Sample ◽  
Surface Relaxivity ◽  
Nmr Parameters ◽  
Low Field ◽  
The Difference ◽  
Coal Reservoir ◽  
Nuclear Magnetic

Low-field nuclear magnetic resonance (LFNMR) is a rapid, nondestructive analytical method which has been proved to be attractive for its application in brittle and easily compressed coals. In this paper, the relationships between NMR parameters and coal pores were analyzed by the NMR measurements of six coal samples with different ranks using AniMR with the resonance frequency of 12.15MHz. Results show that NMR porosity usually compare well to water porosity and be lower than He porosity, and the NMR porosity at echo spacing of 0.3ms sometimes underestimates the coal sample, lower than water porosity by >1 porosity unit. In contrast, the NMR porosity at echo spacing of 0.1ms is acceptable for characterization of coal reservoir. The difference of NMR porosity at different echo spacing may relate to the vitrinite content. Based on the T2c model, the transverse surface relaxivity of coal is calculated and it ranges from 0.25 to 20 um/s, commonly lower than 5um/s. The producible porosity could be a parameter used to estimate coal permeability, however there still needs a lot of work to construct a perfect method for this.

Study of Nuclear Magnetic Resonance on Imbibition Mechanics of Conglomeratic Cores

2011 ◽  
Vol 110-116 ◽  
pp. 4128-4132
Author(s):  
Rui Shen ◽  
Zhi Ming Hu
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Fluid Flows ◽  
Formation Water ◽  
Test Results ◽  
Time Points ◽  
The Difference ◽  
The One ◽  
Nuclear Magnetic

In order to deeply study the imbibition mechanism of conglomerate reservoir, the law that fluid flows in different sizes of pores in the process of imbibition was researched by nuclear magnetic resonance. First, the conglomerate core was saturated by the simulated formation water, and then was saturated by polyfluoroethylene oil to form the irreducible water. During the experiment of imbibition, several time points were selected and the conglomerate core was tested by NMR. According to the relaxation time T2, pores were divided into large, middle and small three size ranges. As the imbibition time increases, the available rate of middle and small pores increase faster than large pores. The available rate of middle and small pores both exceed 50%, but the one of large pores is lower than 35%. The difference of mechanism between imbibition and waterflooding is explained by their NMR test results.

An emerging technology: Nuclear magnetic resonance microscopy

1988 ◽  
Vol 46 ◽  
pp. 1000-1001
Author(s):  
M.J. Hennessy ◽  
E. Kwok
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Basic Research ◽  
Local Environment ◽  
Magnetic Resonance Images ◽  
Nmr Microscopy ◽  
Mri Scans ◽  
Temperature Relaxation ◽  
Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

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