scholarly journals Some Applications of a Field Programmable Gate Array Based Time-Domain Spectrometer for NMR Relaxation and NMR Cryoporometry

2020 ◽  
Vol 10 (8) ◽  
pp. 2714 ◽  
Author(s):  
J. Beau W. Webber
Keyword(s):  
Porous Materials ◽  
Time Domain ◽  
Field Programmable Gate Array ◽  
Material Science ◽  
Variable Temperature ◽  
Nmr Relaxation ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
Field Programmable ◽  
Nmr Cryoporometry

NMR Relaxation (NMRR) is an extremely useful quantitative technique for material science, particularly for studying polymers and porous materials. NMR Cryoporometry (NMRC) is a powerful technique for the measurement of pore-size distributions and total porosities. This paper discusses the use, capabilities and application of a newly available compact NMR time-domain relaxation spectrometer, the Lab-Tools Mk3 NMR Relaxometer & Cryoporometer [Lab-Tools (nano-science), Ramsgate, Kent, UK (2019)]. Being Field Programmable Gate Array based means that it is unusually compact, which makes it particularly suitable for the lab bench-top, in the field and also mobile use. Its use with a variable-temperature NMR probe such as the Lab-Tools Peltier thermo-electrically cooled variable-temperature (V-T) probe is also discussed. This enables the NMRC measurement of pore-size distributions in porous materials, from sub-nano- to over 1 micron sized pores. These techniques are suitable for a wide range of porous materials and also polymers. This instrument comes with a Graphical User Interface (GUI) for control, which also enables both online and offline analysis of the measured data. This makes it is easy to use for material science studies both in the field and in university, research institute, company and even school laboratories. The Peltier cooling gives the precision temperature control and smoothness needed by NMR Cryoporometry, particularly near the probe liquid bulk melting point. Results from example NMR Relaxation and NMR Cryoporometric measurements are given.

scholarly journals Hydraulic characterisation of iron oxide-coated sand and gravel based on nuclear magnetic resonance relaxation modes analyses

2017 ◽  
Author(s):  
Stephan Costabel ◽  
Christoph Weidner ◽  
Mike Müller-Petke ◽  
Georg Houben
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Relaxation Time ◽  
Pore Size ◽  
Nmr Relaxation ◽  
Size Distributions ◽  
Nmr Data ◽  
Pore Size Distributions ◽  
Relaxation Modes ◽  
Sand And Gravel ◽  
Coated Sand

Abstract. The capability of nuclear magnetic resonance (NMR) relaxometry to characterise hydraulic properties of iron oxide-coated sand and gravel was evaluated in a laboratory study. Past studies have shown that the presence of paramagnetic iron oxides and large pores as present in coarse sand and gravel disturbs the otherwise linear relationship between relaxation time and pore size. Consequently, the commonly applied empirical approaches fail when deriving hydraulic quantities from NMR parameters. Recent research demonstrates that higher relaxation modes must be taken into account to relate the size of a large pore to its NMR relaxation behaviour in the presence of significant paramagnetic impurities at its pore wall. We performed NMR relaxation experiments with water-saturated natural and reworked sands and gravels, coated with natural and synthetic ferric oxides (goethite, ferrihydrite) and show that the impact of the higher relaxation modes increases significantly with increasing iron content. Since the investigated materials exhibit narrow pore size distributions, and can thus be described by a virtual bundle of capillaries with identical apparent pore radius, recently presented inversion approaches allow for estimating a unique solution yielding the apparent capillary radius from the NMR data. We found the NMR-based apparent radii to correspond well to the effective hydraulic radii estimated from the grain size distributions of the samples for the entire range of observed iron contents. Consequently, they can be used to estimate the hydraulic conductivity using the well-known Kozeny-Carman equation without any calibration that is otherwise necessary when predicting hydraulic conductivities from NMR data. Our future research will focus on the development of relaxation time models that allow for broader pore size distributions. Furthermore, we plan to establish a measurement system based on borehole NMR for localising iron clogging and controlling its remediation in the gravel pack of groundwater wells.

Pore size distributions of biodegradable polymer microparticles in aqueous environments measured by NMR cryoporometry

2006 ◽  
Vol 309 (1-2) ◽  
pp. 157-162 ◽  
Author(s):  
Oleg Petrov ◽  
István Furó ◽  
Michael Schuleit ◽  
Rainer Domanig ◽  
Mark Plunkett ◽  
...  
Keyword(s):  
Pore Size ◽  
Biodegradable Polymer ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
Aqueous Environments ◽  
Polymer Microparticles ◽  
Nmr Cryoporometry

Upscaling Permeation Properties in Porous Materials from Pore Size Distributions

2013 ◽  
Author(s):  
Fadi Khaddour ◽  
David Grégoire ◽  
Bertrand Guatarbes ◽  
Gilles Pijaudier-Cabot
Keyword(s):  
Porous Materials ◽  
Pore Size ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
Permeation Properties
Sign in / Sign up

Export Citation Format

Share Document