Artykuły w czasopismach: „NMR Measurements”

1

Caprihan, A., i E. Fukushima. "Flow measurements by NMR". Physics Reports 198, nr 4 (grudzień 1990): 195–235. http://dx.doi.org/10.1016/0370-1573(90)90046-5.

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Rollwitz, William. "4701705 NMR moisture measurements". Magnetic Resonance Imaging 6, nr 4 (lipiec 1988): I. http://dx.doi.org/10.1016/0730-725x(88)90485-7.

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Granger, P., M. Bourdonneau, O. Assémat i M. Piotto. "NMR chemical shift measurements revisited: High precision measurements". Concepts in Magnetic Resonance Part A 30A, nr 4 (2007): 184–93. http://dx.doi.org/10.1002/cmr.a.20089.

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Kärger, Jörg, Dieter Freude i Jürgen Haase. "Diffusion in Nanoporous Materials: Novel Insights by Combining MAS and PFG NMR". Processes 6, nr 9 (1.09.2018): 147. http://dx.doi.org/10.3390/pr6090147.

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Pulsed field gradient (PFG) nuclear magnetic resonance (NMR) allows recording of molecular diffusion paths (notably, the probability distribution of molecular displacements over typically micrometers, covered during an observation time of typically milliseconds) and has thus proven to serve as a most versatile means for the in-depth study of mass transfer in complex materials. This is particularly true with nanoporous host materials, where PFG NMR enabled the first direct measurement of intracrystalline diffusivities of guest molecules. Spatial resolution, i.e., the minimum diffusion path length experimentally observable, is limited by the time interval over which the pulsed field gradients may be applied. In “conventional” PFG NMR measurements, this time interval is determined by a characteristic quantity of the host-guest system under study, the so-called transverse nuclear magnetic relaxation time. This leads, notably when considering systems with low molecular mobilities, to severe restrictions in the applicability of PFG NMR. These restrictions may partially be released by performing PFG NMR measurements in combination with “magic-angle spinning” (MAS) of the NMR sample tube. The present review introduces the fundamentals of this technique and illustrates, via a number of recent cases, the gain in information thus attainable. Examples include diffusion measurements with nanoporous host-guest systems of low intrinsic mobility and selective diffusion measurement in multicomponent systems.

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Newling, Benedict. "Gas flow measurements by NMR". Progress in Nuclear Magnetic Resonance Spectroscopy 52, nr 1 (styczeń 2008): 31–48. http://dx.doi.org/10.1016/j.pnmrs.2007.08.002.

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Deng, Feng, Lizhi Xiao, Mengying Wang, Ye Tao, Lulin Kong, Xiaoning Zhang, Xinyun Liu i Dongshi Geng. "Online NMR Flowing Fluid Measurements". Applied Magnetic Resonance 47, nr 11 (6.10.2016): 1239–53. http://dx.doi.org/10.1007/s00723-016-0832-2.

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Suits, B. H., R. W. Siegel i Y. X. Liao. "NMR measurements of nanophase silver". Nanostructured Materials 2, nr 6 (listopad 1993): 597–602. http://dx.doi.org/10.1016/0965-9773(93)90033-8.

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Berkowitz, Bruce A., James T. Handa i Charles A. Wilson. "Perfluorocarbon temperature measurements using19F NMR". NMR in Biomedicine 5, nr 2 (marzec 1992): 65–68. http://dx.doi.org/10.1002/nbm.1940050204.

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Prammer, Manfred G. "Hydrocarbon saturation measurements by NMR". Concepts in Magnetic Resonance 13, nr 6 (2001): 406–8. http://dx.doi.org/10.1002/cmr.1028.

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Leisen, Johannes, Haskell W. Beckham i Michael Benham. "Sorption Isotherm Measurements by NMR". Solid State Nuclear Magnetic Resonance 22, nr 2-3 (wrzesień 2002): 409–22. http://dx.doi.org/10.1006/snmr.2002.0069.

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Grombacher, Denys. "Modelling surface NMR spin-echo experiments in a heterogeneous B1 field". Geophysical Journal International 219, nr 2 (30.08.2019): 1395–404. http://dx.doi.org/10.1093/gji/ggz388.

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SUMMARY Surface nuclear magnetic resonance (NMR) measurements show great promise for characterization of subsurface water content, pore-sizes and permeability. The link between surface NMR and pore-size/permeability is founded in the connection between the NMR signal's time dependence and the geometry of the pore-space. To strengthen links between the NMR signal and pore-geometry multipulse surface NMR sequences have been developed to estimate the parameter T2, which carries a strong link to pore-geometry and has formed the basis for NMR-based permeability estimation in the petroleum industry for decades. Producing reliable subsurface characterizations from multipulse surface NMR measurements that measure T2 requires that the forward model is able to accurately predict the transverse magnetization at the time when the measurement occurs. Traditional surface NMR T2 forward models employ an analytic expression for the transverse magnetization, an expression developed in the context of laboratory NMR experiments conducted under conditions significantly different from surface NMR and which require several assumptions to simplify the underlying Bloch equation. To investigate the reliability of this analytic expression under surface NMR conditions, a synthetic comparison is performed where the analytic expression is contrasted against the transverse magnetization predicted from a solution of the full-Bloch equation without the same simplifying assumptions and which can appropriately weight heterogeneity in the applied and background magnetic fields. The comparison shows that the analytic expression breaks down in a range of conditions typical to surface NMR measurements.

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Legchenko, Anatoly V., i Oleg A. Shushakov. "Inversion of surface NMR data". GEOPHYSICS 63, nr 1 (styczeń 1998): 75–84. http://dx.doi.org/10.1190/1.1444329.

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The main advantage of the surface nuclear magnetic resonance (NMR) method compared to other geophysical methods in the field of groundwater investigation is the ability to measure an NMR signal directly from the water molecules. An NMR signal stimulated by an alternating current pulse through an antenna at the surface, confirms the existence of water in the subsurface with a high degree of reliability. The NMR signal amplitude depends on the pulse parameter (the product of the pulse amplitude and its duration), bulk water volume, and water depth. Measurements are performed while varying the pulse parameter, and subsequent data processing reveals the number of water‐saturated layers, and data concerning their depth, thickness, and water content. One of the major problems in the practical application of the NMR method is the very weak signal (<3000 nV): hence the problem of signal to noise ratio (S/N). S/N can be improved by stacking the signal, but measurement time is increased. We have developed an algorithm that minimizes the number of measurements (number of different values of the pulse parameter) without a loss of inversion accuracy for a given S/N ratio, making it possible to determine a set of optimal pulses for the measurements. NMR measurements are also sensitive to the electrical conductivity of the subsurface; an electrically conductive subsurface causes variations in the depth of investigation and in the vertical resolution of the method. Experience gained from application of the method has proven that both the inversion algorithm and the analysis of the problem are efficient.

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Rief, Martin, Reinhard Raggam, Peter Rief, Philipp Metnitz, Tatjana Stojakovic, Markus Reinthaler, Marianne Brodmann, Winfried März, Hubert Scharnagl i Günther Silbernagel. "Comparison of Two Nuclear Magnetic Resonance Spectroscopy Methods for the Measurement of Lipoprotein Particle Concentrations". Biomedicines 10, nr 7 (21.07.2022): 1766. http://dx.doi.org/10.3390/biomedicines10071766.

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Background: Measuring lipoprotein particle concentrations may help to improve cardiovascular risk stratification. Both the lipofit (Numares) and lipoprofile (LabCorp) NMR methods are widely used for the quantification of lipoprotein particle concentrations. Objective: The aim of the present work was to perform a method comparison between the lipofit and lipoprofile NMR methods. In addition, there was the objective to compare lipofit and lipoprofile measurements of standard lipids with clinical chemistry-based results. Methods: Total, LDL, and HDL cholesterol and triglycerides were measured with ß-quantification in serum samples from 150 individuals. NMR measurements of standard lipids and lipoprotein particle concentrations were performed by Numares and LabCorp. Results: For both NMR methods, differences of mean concentrations compared to ß-quantification-derived measurements were ≤5.5% for all standard lipids. There was a strong correlation between ß-quantification- and NMR-derived measurements of total and LDL cholesterol and triglycerides (all r > 0.93). For both, the lipofit (r = 0.81) and lipoprofile (r = 0.84) methods, correlation coefficients were lower for HDL cholesterol. There was a reasonable correlation between LDL and HDL lipoprotein particle concentrations measured with both NMR methods (both r > 0.9). However, mean concentrations of major and subclass lipoprotein particle concentrations were not as strong. Conclusions: The present analysis suggests that reliable measurement of standard lipids is possible with these two NMR methods. Harmonization efforts would be needed for better comparability of particle concentration data.

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Dillon, Patrick F., i Patrick R. Sears. "Capillary electrophoretic measurement of tissue metabolites". American Journal of Physiology-Cell Physiology 274, nr 3 (1.03.1998): C840—C845. http://dx.doi.org/10.1152/ajpcell.1998.274.3.c840.

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A method for the measurement of tissue metabolites from rabbit urinary bladder using capillary electrophoresis (CE) has been developed. The method generates a reproducible electropherogram containing >20 peaks, including NAD, NADH, lactate, UDP-glucose, phosphocreatine, creatine, ATP, ADP, GTP, and UTP, from <20 nl of extract solution generated from 1.1 nl (or ∼1.2 μg) of tissue in <40 min. Multiple samples from the same bladder produce SE comparable with enzymatic or nuclear magnetic resonance (NMR) measurements of metabolites: phosphorus-NMR measurement requires 106 more tissue than CE; individual enzymatic measurements using 100 μl/sample require 2,000 μl, a 105 greater volume than required by CE for the same number of metabolites. CE detects about three times more peaks than phosphorus-NMR on a similar time scale. Comparable measurements using enzymatic analysis would require ∼10 times longer. The combination of minimal tissue volume requirements, rapid measurement, and reproducibility makes CE a valuable tool in the investigation of simultaneous changes in multiple metabolites from minute tissue samples.

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Ozawa, Kiyoshi, Laurent Guiguard, Sharon Pursglove, Gottfried Otting i Nicholas Dixon. "2R1415 In vitro expression of various proteins for NMR measurements". Seibutsu Butsuri 42, supplement2 (2002): S149. http://dx.doi.org/10.2142/biophys.42.s149_1.

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Buist, Richard J., Roxanne Deslauriers, John K. Saunders i Graham W. Mainwood. "23Na and flame photometric studies of the NMR visibility of sodium in rat muscle". Canadian Journal of Physiology and Pharmacology 69, nr 11 (1.11.1991): 1663–69. http://dx.doi.org/10.1139/y91-247.

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23Na nuclear magnetic resonance spectroscopy (NMR) is increasingly being used to study Na+ gradients and fluxes in biological tissues. However, the quantitative aspects of 23Na NMR applied to living systems remain controversial. This paper compares sodium concentrations determined by 23Na NMR in intact rat hindlimb (n = 8) and excised rat gastrocnemius muscle (n = 4) with those obtained by flame photometric methods. In both types of samples, 90% of the sodium measured by flame photometry was found to be NMR-visible. This is much higher than previously reported values. The NMR measurements for intact hindlimb correlated linearly with the flame photometric measurements, implying that one pool of sodium, predominantly extracellular, is 100% visible. From measurements on excised muscle, in which extracellular space is more clearly defined, the NMR visibility of intracellular Na+ was calculated to be 70%, assuming an extracellular space of 12% of the total tissue water volume and an extracellular NMR visibility of 100%. 23Na transverse relaxation measurements were carried out using a Hahn spin echo on both intact hindlimb (n = 1) and excised muscle (n = 2) samples. These showed relaxation curves that could each be described adequately using two relaxation times. The rapidly relaxing component showed a T2 value of 3–4 ms and the slowly relaxing component a T2 of 21–37 ms. A spin lattice relaxation (T1) measurement on intact hindlimb yielded a value of 51 ms. These relatively long relaxation times show that the quadrupolar relaxation effect of Na+ complexing to large macromolecules or being otherwise motionally restricted is relatively weak. This is consistent with the high NMR visibilities reported here.Key words: Na+, rat hindlimb, gastrocnemius, nuclear magnetic resonance spectroscopy.

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Felix-Gonzalez, N., A. L. Urbano-Bojorge, C. Sanchez-L. de Pablo, V. Ferro-Llanos, F. del Pozo-Guerrero i J. J. Serrano-Olmedo. "Power Absorption Measurements during NMR Experiments". Journal of Magnetics 19, nr 2 (30.06.2014): 155–60. http://dx.doi.org/10.4283/jmag.2014.19.2.155.

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Denney, Dennis. "NMR Measurements To Characterize Gas Reservoirs". Journal of Petroleum Technology 51, nr 11 (1.11.1999): 58–59. http://dx.doi.org/10.2118/1199-0058-jpt.

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Hashi, Kenjiro, Tadashi Shimizu, Atsushi Goto, Takahiro Iijima i Shinobu Ohki. "NMR Measurements with a Hybrid Magnet". Japanese Journal of Applied Physics 43, No. 8A (9.07.2004): L1020—L1022. http://dx.doi.org/10.1143/jjap.43.l1020.

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Allard, Mathieu, i R. Mark Henkelman. "Using metamaterial yokes in NMR measurements". Journal of Magnetic Resonance 182, nr 2 (październik 2006): 200–207. http://dx.doi.org/10.1016/j.jmr.2006.06.029.

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Mullins, T. R., V. V. Dmitriev, A. J. Armstrong, J. R. Hook i H. E. Hall. "Low field NMR measurements in3He-A". Physica B: Condensed Matter 194-196 (luty 1994): 769–70. http://dx.doi.org/10.1016/0921-4526(94)90714-5.

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Singer, Annett, i Wolf Hiller. "Pulsed NMR measurements on polyethylene melts". Polymer Bulletin 14, nr 5 (listopad 1985): 469–75. http://dx.doi.org/10.1007/bf00263464.

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Price, Kristin E., Laura H. Lucas i Cynthia K. Larive. "Analytical applications of NMR diffusion measurements". Analytical and Bioanalytical Chemistry 378, nr 6 (1.03.2004): 1405–7. http://dx.doi.org/10.1007/s00216-003-2410-3.

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Terao, Takehiko. "Structural measurements by solid-state NMR". Journal of Molecular Structure 441, nr 2-3 (styczeń 1998): 283–94. http://dx.doi.org/10.1016/s0022-2860(97)00301-3.

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Meyer, Ronald A., i Truman R. Brown. "Diffusion measurements by microscopic NMR imaging". Journal of Magnetic Resonance (1969) 76, nr 3 (luty 1988): 393–99. http://dx.doi.org/10.1016/0022-2364(88)90345-9.

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Turner, Robert, i Paul Keller. "Angiography and perfusion measurements by NMR". Progress in Nuclear Magnetic Resonance Spectroscopy 23, nr 1 (styczeń 1991): 93–133. http://dx.doi.org/10.1016/0079-6565(91)80003-k.

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Diserens, G., D. Hertig, M. Vermathen, B. Legeza, C. E. Flück, J. M. Nuoffer i P. Vermathen. "Metabolic stability of cells for extended metabolomical measurements using NMR. A comparison between lysed and additionally heat inactivated cells". Analyst 142, nr 3 (2017): 465–71. http://dx.doi.org/10.1039/c6an02195f.

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Kärger, Jörg, Marija Avramovska, Dieter Freude, Jürgen Haase, Seungtaik Hwang i Rustem Valiullin. "Pulsed field gradient NMR diffusion measurement in nanoporous materials". Adsorption 27, nr 3 (9.01.2021): 453–84. http://dx.doi.org/10.1007/s10450-020-00290-9.

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AbstractLabeling in diffusion measurements by pulsed field gradient (PFG) NMR is based on the observation of the phase of nuclear spins acquired in a constant magnetic field with purposefully superimposed field gradients. This labeling does in no way affect microdynamics and provides information about the probability distribution of molecular displacements as a function of time. An introduction of the measuring principle is followed by a detailed description of the ranges of measurements and their limitation. Particular emphasis is given to an explanation of possible pitfalls in the measurements and the ways to circumvent them. Showcases presented for illustrating the wealth of information provided by PFG NMR include a survey on the various patterns of concentration dependence of intra-particle diffusion and examples of transport inhibition by additional transport resistances within the nanoporous particles and on their external surface. The latter information is attained by combination with the outcome of tracer exchange experiments, which are shown to become possible via a special formalism of PFG NMR data analysis. Further evidence provided by PFG NMR concerns diffusion enhancement in pore hierarchies, diffusion anisotropy and the impact of diffusion on chemical conversion in porous catalysts. A compilation of the specifics of PFG NMR and of the parallels with other measurement techniques concludes the paper.

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Brandner, Juergen J. "In-Situ Measurements in Microscale Gas Flows—Conventional Sensors or Something Else?" Micromachines 10, nr 5 (29.04.2019): 292. http://dx.doi.org/10.3390/mi10050292.

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Within the last few decades miniaturization has a driving force in almost all areas of technology, leading to a tremendous intensification of systems and processes. Information technology provides now data density several orders of magnitude higher than a few years ago, and the smartphone technology includes, as well the simple ability to communicate with others, features like internet, video and music streaming, but also implementation of the global positioning system, environment sensors or measurement systems for individual health. So-called wearables are everywhere, from the physio-parameter sensing wrist smart watch up to the measurement of heart rates by underwear. This trend holds also for gas flow applications, where complex flow arrangements and measurement systems formerly designed for a macro scale have been transferred into miniaturized versions. Thus, those systems took advantage of the increased surface to volume ratio as well as of the improved heat and mass transfer behavior of miniaturized equipment. In accordance, disadvantages like gas flow mal-distribution on parallelized mini- or micro tubes or channels as well as increased pressure losses due to the minimized hydraulic diameters and an increased roughness-to-dimension ratio have to be taken into account. Furthermore, major problems are arising for measurement and control to be implemented for in-situ and/or in-operando measurements. Currently, correlated measurements are widely discussed to obtain a more comprehensive view to a process by using a broad variety of measurement techniques complementing each other. Techniques for correlated measurements may include commonly used techniques like thermocouples or pressure sensors as well as more complex systems like gas chromatography, mass spectrometry, infrared or ultraviolet spectroscopy and many others. Some of these techniques can be miniaturized, some of them cannot yet. Those should, nevertheless, be able to conduct measurements at the same location and the same time, preferably in-situ and in-operando. Therefore, combinations of measurement instruments might be necessary, which will provide complementary techniques for accessing local process information. A recently more intensively discussed additional possibility is the application of nuclear magnetic resonance (NMR) systems, which might be useful in combination with other, more conventional measurement techniques. NMR is currently undergoing a tremendous change from large-scale to benchtop measurement systems, and it will most likely be further miniaturized. NMR allows a multitude of different measurements, which are normally covered by several instruments. Additionally, NMR can be combined very well with other measurement equipment to perform correlative in-situ and in-operando measurements. Such combinations of several instruments would allow us to retrieve an “information cloud” of a process. This paper will present a view of some common measurement techniques and the difficulties of applying them on one hand in a miniaturized scale, and on the other hand in a correlative mode. Basic suggestions to achieve the above-mentioned objective by a combination of different methods including NMR will be given.

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Rönnols, Jerk, Ernesto Danieli, Hélène Freichels i Fredrik Aldaeus. "Lignin analysis with benchtop NMR spectroscopy". Holzforschung 74, nr 2 (25.02.2020): 226–31. http://dx.doi.org/10.1515/hf-2018-0282.

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AbstractBenchtop nuclear magnetic resonance (NMR) spectroscopy is an emerging field with an appealing profile for industrial applications. The instrumentation offers the possibility to measure NMR spectra in situations where high-field NMR spectroscopy is considered too expensive or complicated. In this study, we investigated the scope and limitations of 1H NMR measurements on kraft lignins and black liquors at low magnetic field strengths (1.0 and 1.5 T). The ability to quantify different classes of compounds was investigated and found to be promising. NMR-based diffusion measurements were performed, with the aim of gaining insight into the molar mass of the lignins at hand. These measurements were fast, repeatable and in good agreement with established methods.

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Bryan, J., A. Kantzas i C. Bellehumeur. "Oil-Viscosity Predictions From Low-Field NMR Measurements". SPE Reservoir Evaluation & Engineering 8, nr 01 (1.02.2005): 44–52. http://dx.doi.org/10.2118/89070-pa.

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Summary Canada contains vast reserves of heavy oil and bitumen. Viscosity determination is key to the successful recovery of this oil, and low-field nuclear magnetic resonance (NMR) shows great potential as a tool for estimating this property. An NMR viscosity correlation previously had been developed that is valid for order-of-magnitude estimates over a wide range of viscosities and temperatures. This correlation was built phenomenologically, using experiments relating NMR spectra to viscosity. The present work details a more thorough investigation into oil viscosity and NMR, thus providing a theoretical justification for the proposed correlation. A novel tuning procedure is also presented, whereby the correlation is fitted using the Arrhenius relationship to improve the NMR viscosity estimates for single oils at multiple temperatures. Tuning allows for NMR to be potentially used in observation wells to monitor thermal enhanced oil recovery (EOR) projects or online to monitor the viscosity of produced-fluid streams as they cool. Introduction With approximately 400 million m3 of oil in place, the Canadian deposits of heavy oil and bitumen are some of the most vast oil resources in the world.1Heavy oil and bitumen are characterized by high densities and viscosities, which is a major obstacle to their recovery. The waning of conventional-oil reserves in Canada, coupled with increasing worldwide demand for oil, has forced the industry focus to shift rapidly to the exploitation of these heavy-oil and bitumen reserves. The most important physical property of heavy oil that affects its recovery is its viscosity.1 This parameter dictates both the economics and the technical chance of success for any chosen recovery scheme. As a result, oil viscosity is often directly related to recoverable reserves estimates.2 Unfortunately, laboratory measurements of oil viscosity become progressively more difficult to obtain as viscosity increases.3 The oil that has been removed from the core also may have been physically altered during sampling and transport. Thus, the viscosity at reservoir conditions may be different from the value obtained later from the laboratory.2 In light of the shortcomings of conventional viscosity measurements, low-field NMR is considered as an alternative for estimating heavy-oil and bitumen viscosity. The main appeal of NMR as a tool for assessing reservoir-fluid viscosities and phase volumes is that the measured signal comes only from hydrogen, which is present in both oil and water found in hydrocarbon reservoirs.4,5 Most of the low-field NMR applications in the petroleum industry have been inconventional oil, contained in sandstone reservoirs.6 To use low-field NMR technology in heavy-oil and bitumen formations like the ones present in Alberta, new methods of interpretation are required. The eventual goal for using NMR to estimate viscosity is to make these predictions in the field through logs. Currently, research toward this goal is conducted in the laboratory. In previous work,7-9 an oil-viscosity correlation was presented that is capable of providing viscosity predictions for samples with viscosities less than 1 mPa×s to more than 3 000 000 mPa×s. This is a wider range than any other viscosity correlation presented in the literature.10–15 The correlation is only order-of-magnitude accurate but still could be valuable for applications on a logging tool, where the goal would be to determine viscosity variations with depth or areal location in a reservoir. The theoretical justification behind the NMR correlation is given in this work, along with a procedure for tuning the correlation to improve the viscosity predictions for individual oils as a function of temperature. Low-field NMR experiments are simple to perform and nondestructive. The same test also can be run by different technicians to yield the same results, which is a concern for conventional viscosity tests.3 In this manner, a properly calibrated NMR model for viscosity can be a very accurate and useful tool for predicting heavy-oil and bitumen viscosity at different temperatures.

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Dick, M. J., D. Veselinovic i D. Green. "Spatially resolved wettability measurements using nmr wettability index". E3S Web of Conferences 89 (2019): 03001. http://dx.doi.org/10.1051/e3sconf/20198903001.

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Wettability is a crucial petrophysical parameter for determining accurate production rates in oil and gas reservoirs. However, industry standard wettability measurements (Amott Test and USBM) are expensive and time consuming. It is known that NMR response varies as a function of wettability change in rock core plug samples. This information was used to develop an NMR wettability index (NWI) based on T2 distributions. This NWI is capable of measuring changes in wettability as a function of oil/water saturations unlike traditional methods which are based on measurements at Swi and Sor only. In addition, these oil/water saturations are determined without the aid of any special oil or brine, such as D2O. This allows the NMR method to nondestructively monitor changes in wettability in real time (i.e. during a flooding experiment or an aging procedure). In this work, we have coupled this T2-based NWI to spatially resolved T2 NMR measurements to monitor changes in wettability and saturation along rock core plugs. In order to derive an NMR wettability index, NMR T2 spectra of 100% brine saturated, 100% oil saturated, bulk oil and bulk brine are needed. These spectra are then mixed to give a predicted T2 spectrum which is compared (via a least squares fit) to a T2 spectrum recorded from a sample partially saturated with both water and oil and whose wettability is to be determined. For initial testing, three sandstone samples were employed along with 2% KCl brine and dodecane. To achieve sample states of mixed wettability, 100% brine saturated samples had dodecane pushed into them via centrifugation. Centrifugation at different speeds resulted in samples of varying bulk and spatial wettabilities from which NWI parameters and oil/water saturations were determined. The bulk wettabilities were compared to measurements done using the standard Amott test and oil/water saturations were confirmed by repeating experiments using NMR invisible D2O.

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Power, J. E., M. Foroozandeh, R. W. Adams, M. Nilsson, S. R. Coombes, A. R. Phillips i G. A. Morris. "Increasing the quantitative bandwidth of NMR measurements". Chemical Communications 52, nr 14 (2016): 2916–19. http://dx.doi.org/10.1039/c5cc10206e.

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Fukumori, Kenzo, Norio Sato i Toshio Kurauchi. "Pulsed NMR Study of Motional Heterogeneity in Acrylonitrile-Butadiene/Poly(Vinyl Chloride) Blends". Rubber Chemistry and Technology 64, nr 4 (1.09.1991): 522–33. http://dx.doi.org/10.5254/1.3538570.

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Abstract Motional heterogeneity in blends of NBR (AN = 38%) and PVC was studied by 1H pulsed NMR. It was estimated from NMR relaxation measurements that the PVC molecules in the NBR phase form phase domains of the order of less than 10 nm, consistent with the microheterogeneous structure observed by TEM. Furthermore, by spin diffusion experiments using the Goldman-Shen pulse sequence, the size of the PVC phase domains was semiquantitatively evaluated to be 4.2 nm in the case of the cylindrical domains and to be 5.1 nm in the case of the spherical domains. It becomes clear that pulsed NMR complements the results of other analytical methods with more detailed information on the state of the molecular mixing in the blends.

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Hiller, Thomas, i Norbert Klitzsch. "Joint inversion of nuclear magnetic resonance data from partially saturated rocks using a triangular pore model". GEOPHYSICS 83, nr 4 (1.07.2018): JM15—JM28. http://dx.doi.org/10.1190/geo2017-0697.1.

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Measurement of nuclear magnetic resonance (NMR) relaxation is a well-established laboratory/borehole method to characterize the storage and transport properties of rocks due to its direct sensitivity to the corresponding pore-fluid content (water/oil) and pore sizes. Using NMR, the correct estimation of, e.g., permeability strongly depends on the underlying pore model. Usually, one assumes spherical or cylindrical pores for interpreting NMR relaxation data. To obtain surface relaxivity and thus, the pore-size distribution, a calibration procedure by, e.g., mercury intrusion porosimetry or gas adsorption has to be used. Recently, a joint inversion approach was introduced that used NMR measurements at different capillary pressures/saturations (CPS) to derive surface relaxivity and pore-size distribution (PSD) simultaneously. We further extend this approach from a bundle of parallel cylindrical capillaries to capillaries with triangular cross sections. With this approach, it is possible to account for residual or trapped water within the pore corners/crevices of partially saturated pores. In addition, we have developed a method that allows determining the shape of these triangular capillaries by using NMR measurements at different levels of drainage and imbibition. We show the applicability of our approach on synthetic and measured data sets and determine how the combination of NMR and CPS significantly improves the interpretation of NMR relaxation data on fully and partially saturated porous media.

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Medellin, David, Vivek Ramachandran Ravi i Carlos Torres-Verdín. "Pore-size-dependent fluid substitution method for magnetic resonance measurements". GEOPHYSICS 84, nr 1 (1.01.2019): D25—D38. http://dx.doi.org/10.1190/geo2017-0457.1.

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Pore-size distribution and permeability can be accurately estimated from nuclear magnetic resonance (NMR) measurements acquired in single-fluid-saturated rocks. However, most rocks penetrated by wells contain multiple fluids and are commonly affected by mud-filtrate invasion, which makes the analysis and interpretation of longitudinal ([Formula: see text]) and transverse ([Formula: see text]) relaxation measurements challenging. It is necessary to replace the hydrocarbon NMR response of the original measurements with an equivalent water response to estimate petrophysical quantities of interest. We have developed an improved NMR fluid substitution method that takes into account partial water and hydrocarbon pore saturation and does not require knowledge of permeability and surface relaxivity. The method consists of two steps: first, the hydrocarbon NMR response is removed from the initially water-hydrocarbon-saturated NMR data. Then, the NMR distribution of the resulting hydrocarbon-depleted system is transformed to that of a completely water-saturated system. Four pore-size-dependent saturation distributions are considered in the study. Tests of verification are performed on Berea sandstone and Indiana limestone samples. Our results show that the method can be reliably applied to Berea sandstone but has limited applicability to the Indiana limestone samples.

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Freedman, R., N. Heaton, M. Flaum, G. J. Hirasaki, C. Flaum i M. Hürlimann. "Wettability, Saturation, and Viscosity From NMR Measurements". SPE Journal 8, nr 04 (1.12.2003): 317–27. http://dx.doi.org/10.2118/87340-pa.

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Hrabe, Jan, Gurjinder Kaur i DavidN Guilfoyle. "Principles and limitations of NMR diffusion measurements". Journal of Medical Physics 32, nr 1 (2007): 34. http://dx.doi.org/10.4103/0971-6203.31148.

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39

Takahashi, S. "NMR Measurements in Solutions of Dialkylimidazolium Haloaluminates". ECS Proceedings Volumes 1992-16, nr 1 (styczeń 1992): 345–50. http://dx.doi.org/10.1149/199216.0345pv.

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40

DESBOIS, PASCAL, i DENIS BOTLAN. "Proton Low-Field NMR Measurements on Crackers". Journal of Food Science 59, nr 5 (wrzesień 1994): 1088–90. http://dx.doi.org/10.1111/j.1365-2621.1994.tb08197.x.

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41

Bowman, R. C., B. D. Craft, W. E. Tadlock, E. L. Venturini i J. S. Cantrell. "Proton NMR and susceptibility measurements in TiCoHx". Journal of Applied Physics 57, nr 8 (15.04.1985): 3036–38. http://dx.doi.org/10.1063/1.335204.

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Adebahr, J. "7Li NMR measurements of polymer gel electrolytes". Solid State Ionics 147, nr 3-4 (kwiecień 2002): 303–7. http://dx.doi.org/10.1016/s0167-2738(02)00014-0.

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Fleury, Marc, Françoise Deflandre i Sophie Godefroy. "Validity of permeability prediction from NMR measurements". Comptes Rendus de l'Académie des Sciences - Series IIC - Chemistry 4, nr 11 (listopad 2001): 869–72. http://dx.doi.org/10.1016/s1387-1609(01)01343-3.

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Godejohann, Markus, Alfred Preiss i Clemens Mügge. "Quantitative Measurements in Continuous-Flow HPLC/NMR". Analytical Chemistry 70, nr 3 (luty 1998): 590–95. http://dx.doi.org/10.1021/ac970630s.

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Borgia, G. C., V. Bortolotti, A. Brancolini, R. J. S. Brown i P. Fantazzini. "Developments in core analysis by NMR measurements". Magnetic Resonance Imaging 14, nr 7-8 (styczeń 1996): 751–60. http://dx.doi.org/10.1016/s0730-725x(96)00160-9.

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Brindle, Kevin M., Bheeshma Rajagopalan, Donald S. Williams, John A. Detre, Elena Simplaceanu, Chien Ho i George K. Radda. "31P NMR measurements of myocardial pH invivo". Biochemical and Biophysical Research Communications 151, nr 1 (luty 1988): 70–77. http://dx.doi.org/10.1016/0006-291x(88)90560-8.

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Ohya, S., K. Nishimura i N. Mutsuro. "NMR-ON measurements of187WFe,182,183,186ReNi,186ReFe and203PbFe". Hyperfine Interactions 36, nr 3-4 (październik 1987): 219–33. http://dx.doi.org/10.1007/bf02395631.

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Ihara, Yoshihiko, Kenji Ishida, Kazuyoshi Yoshimura, Kazunori Takada, Takayoshi Sasaki, Hiroya Sakurai i Eiji Takayama-Muromachi. "17O NMR Measurements on Superconducting Na0.35CoO2·yH2O". Journal of the Physical Society of Japan 74, nr 8 (sierpień 2005): 2177–80. http://dx.doi.org/10.1143/jpsj.74.2177.

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Carretta, P., S. Aldrovandi, R. Sala, P. Ghigna i A. Lascialfari. "Spin dynamics inSr14Cu24O41from63CuNQR-NMR and susceptibility measurements". Physical Review B 56, nr 22 (1.12.1997): 14587–96. http://dx.doi.org/10.1103/physrevb.56.14587.

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Sullivan, N. S., J. A. Hamida, S. Pilla, K. A. Muttalib i E. Genio. "Molecular glasses: NMR and dielectric susceptibility measurements". Journal of Structural Chemistry 57, nr 2 (marzec 2016): 301–7. http://dx.doi.org/10.1134/s0022476616020098.

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