Rapid characterization of emulsions by pulsed field gradient nuclear magnetic resonance

A method for rapid characterization of emulsions is presented. From the proposed setup we are able to measure the droplet size distribution of brine or water droplets confined by an oil phase, even though there is complete overlap in relaxation times and/or molecular mobility between the water and the oil phases. A PFG-NMR sequence is presented that applies the spoiler recovery method for significant reduction in acquisition time, and the method is used for rapid characterization of emulsions

A spoiler recovery method for rapid diffusion measurements

A method for rapid acquisition of multiple scans of NMR sequences is presented. The method initially applies two RF-pulses in combination with two magnetic field gradient pulses of opposite polarity, different strength and different duration. The basic idea is to spoil any magnetization in any direction before by letting the system recover to some degree of restoration of the thermal equilibrium magnetization. Thereafter any pulse sequence can be applied, and the next scan may be run immediately after the end of the pulse sequence. Thus one avoids the 5 times T1 delay between each scan. A set of PFG sequences are presented that apply the spoiler recovery method for significant reduction in acquisition time, and the method has been verified at 0.5 Tesla as well as at 11.7 Tesla

Absolute pore size distributions from NMR

NMR measurements on core samples saturated with brine returns valuable information on the porous structure of the rock core. Monitoring a single fluid component in a relaxation experiment reflects the pore size distribution and thus the degree of sorting of the porous rock. The basic assumptions are that the mobility of the component confined in the porous rock is of such a value that a small fraction of the probing molecules experience the surfaces of the pores and that the surface relaxation strength is fairly independent of pore size. Then one may combine diffusion measurements at short observation times returning a value for the average surface to volume ratio with ordinary relaxation time measurements to obtain an absolute pore size distribution instead of the standard T2 distributions or T1-T2 correlated two dimensional distributions

Dynamic pulsed-field-gradient NMR

Dealing with the basics, theory and applications of dynamic pulsed-field-gradient NMR NMR (PFG NMR), this book describes the essential theory behind diffusion in heterogeneous media that can be combined with NMR measurements to extract important information of the system being investigated. This information could be the surface to volume ratio, droplet size distribution in emulsions, brine profiles, fat content in food stuff, permeability/connectivity in porous materials and medical applications currently being developed. Besides theory and applications it will provide the readers with background knowledge on the experimental set-ups, and most important, deal with the pitfalls that are numerously present in work with PFG-NMR. How to analyze the NMR data and some important basic knowledge on the hardware will be explained, too

Rapid characterization of emulsions by pulsed field gradient nuclear magnetic resonance

A method for rapid characterization of emulsions is presented. From the proposed setup we are able to measure the droplet size distribution of brine or water droplets confined by an oil phase, even though there is complete overlap in relaxation times and/or molecular mobility between the water and the oil phases. A PFG-NMR sequence is presented that applies the spoiler recovery method for significant reduction in acquisition time, and the method is used for rapid characterization of emulsions

Quantitative recovery ordered (Q-ROSY) and diffusion: ordered spectroscopy using the spoiler recovery: approach

Combined PFG and T1 methods for rapid acquisition of multiple scans of an NMR pulse sequence are presented. The methods apply initially two RF-pulses in combination with two magnetic field gradient pulses of opposite polarity, different strengths and different durations. The basic idea is to spoil any magnetization in any direction before letting the system recover to some degree of restoration of the thermal equilibrium magnetization. Thereafter any pulse sequence can be applied, and the next scan may be run immediately after the end of this spoiler pulse sequence. Thus one avoids the 5 times T1 delay between each scan. The method has been verified at 11.7 Tesla correlating spectral information with T1 or diffusion

Rapid characterization of emulsions by pulsed field gradient nuclear magnetic resonance

A method for rapid characterization of emulsions is presented. From the proposed setup we are able to measure the droplet size distribution of brine or water droplets confined by an oil phase, even though there is complete overlap in relaxation times and/or molecular mobility between the water and the oil phases. A PFG-NMR sequence is presented that applies the spoiler recovery method for significant reduction in acquisition time, and the method is used for rapid characterization of emulsions

Rheological properties of highly concentrated dense packed layer emulsions (w/o) stabilized by asphaltene

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PROBING THE CONNECTIVITY BETWEEN PORES IN ROCK CORE SAMPLES

ABSTRACT By Nuclear Magnetic Resonance (NMR) measurements of relaxation and diffusion at a predefined observation time in 100 % brine saturated rock core samples it is possible to probe the connectivity between the pores within the sample. By plotting the observation time dependent diffusion coefficients as a function of the surface-to-volume ratio characteristic for each sample, it is possible to compare the connectivity between rock core samples

A spoiler recovery method for rapid diffusion measurements

A method for rapid acquisition of multiple scans of NMR sequences is presented. The method initially applies two RF-pulses in combination with two magnetic field gradient pulses of opposite polarity, different strength and different duration. The basic idea is to spoil any magnetization in any direction before by letting the system recover to some degree of restoration of the thermal equilibrium magnetization. Thereafter any pulse sequence can be applied, and the next scan may be run immediately after the end of the pulse sequence. Thus one avoids the 5 times T1 delay between each scan. A set of PFG sequences are presented that apply the spoiler recovery method for significant reduction in acquisition time, and the method has been verified at 0.5 Tesla as well as at 11.7 Tesla