Nuclear-magnetic-resonance determinations of fluorine content and relaxation times in bone powder

1986 ◽  
Vol 64 (3) ◽  
pp. 282-288 ◽  
Author(s):  
M. E. Ebifegha ◽  
R. F. Code ◽  
K. G. McNeill ◽  
M. Szyjkowski
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Fluorine Content ◽  
Spin Lattice Relaxation ◽  
Relaxation Processes ◽  
Fluorine Concentration ◽  
Bone Powder ◽  
Rat Bone ◽  
Nuclear Magnetic

The detection of trace amounts of fluoride ions from ground rat-bone samples using a 27-MHz solid-state single-coil pulsed nuclear-magnetic-resonance (NMR) spectrometer is described. The fluorine content in the bone samples as determined from the amplitudes of the free-induction-decay (FID) signals is in good agreement with analyses based on standard chemical and neutron-activation techniques. The value of the spin-lattice relaxation time T1 is 1.46 ± 0.07 s in dry rat-bone powder and is slightly longer in wet bone powder depending on the water content. The contribution of cross-relaxation processes to these results is discussed. The value of the spin–spin relaxation time T2 (as determined from the point where the 19F FID signal has decayed to 1/e of its maximum amplitude) is approximately 75 μs. The Hahn echo sequence [(π/2)0-τ-(π)0] applied to 7 g of bone powder with a fluorine concentration of 3 mg F/g bone in a relatively homogeneous region of the external magnetic field yields echoes that persist for times 2τ up to ~0.5 ms.

scholarly journals Imaging of nuclear magnetic resonance spin–lattice relaxation activation energy in cartilage

2018 ◽  
Vol 5 (7) ◽  
pp. 180221 ◽  
Author(s):  
R. J. Foster ◽  
R. A. Damion ◽  
M. E. Ries ◽  
S. W. Smye ◽  
D. G. McGonagle ◽  
...  
Keyword(s):  
Activation Energy ◽  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Cartilage Tissue ◽  
Spin Lattice ◽  
Resonance Spin ◽  
Nuclear Magnetic

Samples of human and bovine cartilage have been examined using magnetic resonance imaging to determine the proton nuclear magnetic resonance spin–lattice relaxation time, T 1 , as a function of depth within through the cartilage tissue. T 1 was measured at five to seven temperatures between 8 and 38°C. From this, it is shown that the T 1 relaxation time is well described by Arrhenius-type behaviour and the activation energy of the relaxation process is quantified. The activation energy within the cartilage is approximately 11 ± 2 kJ mol −1 with this notably being less than that for both pure water (16.6 ± 0.4 kJ mol −1 ) and the phosphate-buffered solution in which the cartilage was immersed (14.7 ± 1.0 kJ mol −1 ). It is shown that this activation energy increases as a function of depth in the cartilage. It is known that cartilage composition varies with depth, and hence, these results have been interpreted in terms of the structure within the cartilage tissue and the association of the water with the macromolecular constituents of the cartilage.

scholarly journals The Use of Solid State NMR to Characterize High Density Polyethylene/Organoclay Nanocomposites

2009 ◽  
Vol 3 (3) ◽  
pp. 187-190
Author(s):  
Tathiane Rodrigues ◽  
◽  
Maria Tavares ◽  
Igor Soares ◽  
Ana Moreira ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Solid State ◽  
Magnetic Resonance ◽  
High Density Polyethylene ◽  
Melt Processing ◽  
Proton Spin ◽  
High Density ◽  
Spin Lattice Relaxation ◽  
Nuclear Magnetic

Recently the development of new materials, in special polymeric nanocomposites, formed by polymer and layered silicates, have gained attention. In this work nanocomposites based on high-density polyethylene matrix (HDPE) and organically modified clay were prepared by melt processing and characterized by the determination of proton spin-lattice relaxation time through solid state nuclear magnetic resonance (NMR) spectroscopy. This work has a proposal to add one quantitative technique to help the researchers to better evaluate polymeric nanocomposite, because NMR is an important tool employed to study both molecular structure and dynamic molecular behavior. The nanocomposites were mixed in a twin-screw extruder, varying the shear rate parameter: 60 and 90 rpm at 463 K. Nanocomposites obtained were characterized through X-ray diffraction; thermal analysis; impact resistance and nuclear magnetic resonance. The T1H results showed that the samples present different molecular domains according to the clay dispersion, forming an intercalated and/or exfoliated nanocomposites. The measurement of relaxation time, using low field NMR, is a useful method to evaluate changes in the molecular mobility of nanocomposite and can infer whether the sample is exfoliated and/or intercalated, since lamellar filler is used.

A new nuclear magnetic resonance property of lung

1985 ◽  
Vol 58 (3) ◽  
pp. 759-762 ◽  
Author(s):  
A. H. Morris ◽  
D. D. Blatter ◽  
T. A. Case ◽  
A. G. Cutillo ◽  
D. C. Ailion ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Spin Lattice Relaxation ◽  
Surrounding Tissue ◽  
Proton Density ◽  
Lung Inflation ◽  
Body Tissues ◽  
Regional Lung ◽  
Nuclear Magnetic

Inflated lung has a nuclear magnetic resonance (NMR) free-induction decay (FID) which is short compared with that of collapsed lung and those of other body tissues. An almost identically short FID is obtained from a slurry of 5-micron alumina particles in water. Interfaces between air and water in lung and between alumina and water in the slurry appear to be the source of spatial internal magnetic inhomogeneities which produce NMR line broadening and the short FID. Paired images that included lung, taken with paired symmetric and asymmetric NMR spin-echo sequences, permit the generation of an image, by subtraction, of the lung isolated from surrounding tissue. These new lung images are neither proton density, T1 (spin-lattice relaxation time), nor T2 (spin-spin relaxation time) images. They complement current NMR images and provide information about regional lung inflation. This previously unrecognized NMR property of lung tissue has potential application in NMR imaging, in quantitative determination of lung water and its distribution, and in the quantitation of regional lung inflation.

Textural and pore size analysis of carbonates from integrated core and nuclear magnetic resonance logging: An Arbuckle study

2015 ◽  
Vol 3 (1) ◽  
pp. SA77-SA89 ◽  
Author(s):  
John Doveton ◽  
Lynn Watney
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Pore Size ◽  
Relaxation Times ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Nmr Logging ◽  
The Core ◽  
Nuclear Magnetic

The T2 relaxation times recorded by nuclear magnetic resonance (NMR) logging are measures of the ratio of the internal surface area to volume of the formation pore system. Although standard porosity logs are restricted to estimating the volume, the NMR log partitions the pore space as a spectrum of pore sizes. These logs have great potential to elucidate carbonate sequences, which can have single, double, or triple porosity systems and whose pores have a wide variety of sizes and shapes. Continuous coring and NMR logging was made of the Cambro-Ordovician Arbuckle saline aquifer in a proposed CO2 injection well in southern Kansas. The large data set gave a rare opportunity to compare the core textural descriptions to NMR T2 relaxation time signatures over an extensive interval. Geochemical logs provided useful elemental information to assess the potential role of paramagnetic components that affect surface relaxivity. Principal component analysis of the T2 relaxation time subdivided the spectrum into five distinctive pore-size classes. When the T2 distribution was allocated between grainstones, packstones, and mudstones, the interparticle porosity component of the spectrum takes a bimodal form that marks a distinction between grain-supported and mud-supported texture. This discrimination was also reflected by the computed gamma-ray log, which recorded contributions from potassium and thorium and therefore assessed clay content reflected by fast relaxation times. A megaporosity class was equated with T2 relaxation times summed from 1024 to 2048 ms bins, and the volumetric curve compared favorably with variation over a range of vug sizes observed in the core. The complementary link between grain textures and pore textures was fruitful in the development of geomodels that integrates geologic core observations with petrophysical log measurements.

Nuclear Magnetic Resonance Studies of δ-Stabilized Plutonium

2003 ◽  
Vol 802 ◽  
Author(s):  
N. J. Curro ◽  
L. Morales
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Low Frequency ◽  
Lattice Relaxation ◽  
Spin Fluctuations ◽  
Spin Lattice Relaxation ◽  
Cubic Symmetry ◽  
Magnetic Resonance Studies ◽  
Local Distortions ◽  
Nuclear Magnetic

Nuclear Magnetic Resonance studies of Ga stabilized δ-Pu reveal detailed information about the local distortions surrounding the Ga impurities as well as provides information about the local spin fluctuations experienced by the Ga nuclei. The Ga NMR spectrum is inhomogeneously broadened by a distribution of local electric field gradients (EFGs), which indicates that the Ga experiences local distortions from cubic symmetry. The Knight shift and spin lattice relaxation rate indicate that the Ga is dominantly coupled to the Fermi surface via core polarization, and is inconsistent with magnetic order or low frequency spin correlations.

Nuclear magnetic resonance (NMR) studies of sintering effects on the lithium ion dynamics in Li1.5Al0.5Ti1.5(PO4)3

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Edda Winter ◽  
Philipp Seipel ◽  
Tatiana Zinkevich ◽  
Sylvio Indris ◽  
Bambar Davaasuren ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Lithium Ion ◽  
Magic Angle Spinning ◽  
Spin Lattice Relaxation ◽  
Magic Angle ◽  
Nmr Studies ◽  
Lithium Ions ◽  
Jump Dynamics ◽  
Nuclear Magnetic

Abstract Various nuclear magnetic resonance (NMR) methods are combined to study the structure and dynamics of Li1.5Al0.5Ti1.5(PO4)3 (LATP) samples, which were obtained from sintering at various temperatures between 650 and 900 °C. 6Li, 27Al, and 31P magic angle spinning (MAS) NMR spectra show that LATP crystallites are better defined for higher calcination temperatures. Analysis of 7Li spin-lattice relaxation and line-shape changes indicates the existence of two species of lithium ions with clearly distinguishable jump dynamics, which can be attributed to crystalline and amorphous sample regions, respectively. An increase of the sintering temperature leads to higher fractions of the fast lithium species with respect to the slow one, but hardly affects the jump dynamics in either of the phases. Specifically, the fast and slow lithium ions show jumps in the nanoseconds regime near 300 and 700 K, respectively. The activation energy of the hopping motion in the LATP crystallites amounts to ca. 0.26 eV. 7Li field-gradient diffusometry reveals that the long-range ion migration is limited by the sample regions featuring slow transport. The high spatial resolution available from the high static field gradients of our setup allows the observation of the lithium ion diffusion inside the small (<100 nm) LATP crystallites, yielding a high self-diffusion coefficient of D = 2 × 10−12 m2/s at room temperature.

scholarly journals Estimation of the permeability of hydrocarbon reservoir samples using induced polarization and nuclear magnetic resonance methods

Geophysics ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. MR73-MR84 ◽  
Author(s):  
Fatemeh Razavirad ◽  
Myriam Schmutz ◽  
Andrew Binley
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Magnetic Resonance ◽  
Mechanistic Model ◽  
Transverse Relaxation Time ◽  
Induced Polarization ◽  
Permeability Model ◽  
Transverse Relaxation ◽  
Hydrocarbon Reservoir ◽  
Nuclear Magnetic

We have evaluated several published models using induced polarization (IP) and nuclear magnetic resonance (NMR) measurements for the estimation of permeability of hydrocarbon reservoir samples. IP and NMR measurements were made on 30 samples (clean sands and sandstones) from a Persian Gulf hydrocarbon reservoir. We assessed the applicability of a mechanistic IP-permeability model and an empirical IP-permeability model recently proposed. The mechanistic model results in a broader range of permeability estimates than those measured for sand samples, whereas the empirical model tends to overestimate the permeability of the samples that we tested. We also evaluated an NMR permeability prediction model that is based on porosity [Formula: see text] and the mean of the log transverse relaxation time ([Formula: see text]). This model provides reasonable permeability estimations for the clean sandstones that we tested but relies on calibrated parameters. We also examined an IP-NMR permeability model, which is based on the peak of the transverse relaxation time distribution, [Formula: see text] and the formation factor. This model consistently underestimates the permeability of the samples tested. We also evaluated a new model. This model estimates the permeability using the arithmetic mean of log transverse NMR relaxation time ([Formula: see text]) and diffusion coefficient of the pore fluid. Using this model, we improved estimates of permeability for sandstones and sand samples. This permeability model may offer a practical solution for geophysically derived estimates of permeability in the field, although testing on a larger database of clean granular materials is needed.

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