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E. O. Fridjonsson D. Bernin J. D. Seymour M. Nydén S. L. Codd 《The European physical journal. E, Soft matter》2011,34(2):18
The displacement scale dependent molecular dynamics of solvent water molecules flowing through b \beta -lactoglobulin gels are measured by pulse gradient spin echo (PGSE) nuclear magnetic resonance (NMR). Gels formed under different
p H conditions generate structures which are characterized by magnetic resonance imaging (MRI) and PGSE NMR measured dynamics
as homogeneous and heterogeneous. The data presented clearly demonstrate the applicability of the theoretical framework for
modeling hydrodynamic dispersion to the analysis of protein gels. 相似文献
2.
Lingwood IA Chandrasekera TC Kolz J Fridjonsson EO Johns ML 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2012,214(1):281-288
Pulsed Field Gradient (PFG) measurements are commonly used to determine emulsion droplet size distributions based on restricted self-diffusion within the emulsion droplets. Such measurement capability is readily available on commercial NMR bench-top apparatus. A significant limitation is the requirement to selectively detect signal from the liquid phase within the emulsion droplets; this is currently achieved using either relaxation or self-diffusion contrast. Here we demonstrate the use of a 1.1 T bench-top NMR magnet, which when coupled with an rf micro-coil, is able to provide sufficient chemical shift resolution such that unambiguous signal selection is achieved from the dispersed droplet phase. We also improve the accuracy of the numerical inversion process required to produce the emulsion droplet size distribution, by employing the Block Gradient Pulse (bgp) method, which partially relaxes the assumptions of a Gaussian phase distribution or infinitely short gradient pulse application inherent in current application. The techniques are successfully applied to size 3 different emulsions. 相似文献
3.
Dynamic NMR microscopy measurement of the dynamics and flow partitioning of colloidal particles in a bifurcation 总被引:1,自引:0,他引:1
Einar O. Fridjonsson Joseph D. Seymour Giles R. Cokelet Sarah L. Codd 《Experiments in fluids》2011,50(5):1335-1347
The flow and distribution of Newtonian, polymeric and colloid suspension fluids at low Reynolds numbers in bifurcations has
importance in a wide range of disciplines, including microvascular physiology and microfluidic devices. A bifurcation consisting
of circular capillaries laser etched into a hard polymer with inlet diameter 2.50 ± 0.01 mm, bifurcating to a small diameter
outlet of 0.76 ± 0.01 mm and a large diameter outlet of 1.25 ± 0.01 mm is examined. Four distinct fluids (water, 0.25%wt xanthan
gum, 8 and 22%vol hard-sphere colloidal suspensions) are flowed at flow rates from 10 to 30 ml/h corresponding to Reynolds
numbers based on the entry flow from 0.001 to 8. PGSE NMR techniques are applied to obtain dynamic images of the fluids inside
the bifurcation with spatial resolution of 59 × 59 μm/pixel in plane over a 200-μm-thick slice. Velocity in all three spatial
directions is examined to determine the impact of secondary flows and characterize the transport in the bifurcation. The velocity
data provide direct measurement of the volumetric distribution of the flow between the two channels as a function of flow
rate. Water and the 8% colloidal suspension show a constant distribution with increasing flow rate, the xanthan gum shows
an increase in fluid going into the larger outlet with higher flow rate, and the 22% colloidal suspension shows a decrease
in fluid entering the larger channel with higher flow rate. For the colloidal particle flow, the distribution of colloid particles
down the capillary is determined by examining the spectrally resolved propagator for the oil inside the core–shell particles
in a direction perpendicular to the axial flow. Using dynamic magnetic resonance microscopy, the potential for using magnetic
resonance for “particle counting” in a microscale bifurcation is thus demonstrated. 相似文献
4.
Fridjonsson EO Bernin D Seymour JD Nydén M Codd SL 《The European physical journal. E, Soft matter》2011,34(3):1-15
The displacement scale dependent molecular dynamics of solvent water molecules flowing through β-lactoglobulin gels are measured by pulse gradient spin echo (PGSE) nuclear magnetic resonance (NMR). Gels formed under different p H conditions generate structures which are characterized by magnetic resonance imaging (MRI) and PGSE NMR measured dynamics as homogeneous and heterogeneous. The data presented clearly demonstrate the applicability of the theoretical framework for modeling hydrodynamic dispersion to the analysis of protein gels. 相似文献
5.
Fridjonsson EO Bernin D Seymour JD Nydén M Codd SL 《The European physical journal. E, Soft matter》2011,34(2):1-15
The displacement scale dependent molecular dynamics of solvent water molecules flowing through [Formula: see text] -lactoglobulin gels are measured by pulse gradient spin echo (PGSE) nuclear magnetic resonance (NMR). Gels formed under different p H conditions generate structures which are characterized by magnetic resonance imaging (MRI) and PGSE NMR measured dynamics as homogeneous and heterogeneous. The data presented clearly demonstrate the applicability of the theoretical framework for modeling hydrodynamic dispersion to the analysis of protein gels. 相似文献
6.
Brown JR Seymour JD Codd SL Fridjonsson EO Cokelet GR Nydén M 《Physical review letters》2007,99(24):240602
Magnetic resonance measurements of migration and irreversible dynamics in the capillary shear flow of a Brownian suspension are presented. The results demonstrate the presence of phenomena typically associated with concentrated noncolloidal systems and indicate the role of many body hydrodynamics in dilute Brownian suspension transport. The application of concepts from chaos theory and nonequilibrium statistical mechanics is demonstrated. 相似文献
7.
E. O. Fridjonsson D. Bernin J. D. Seymour M. Nydén S. L. Codd 《The European physical journal. E, Soft matter》2011,34(3):29
The displacement scale dependent molecular dynamics of solvent water molecules flowing through b \beta -lactoglobulin gels are measured by pulse gradient spin echo (PGSE) nuclear magnetic resonance (NMR). Gels formed under different
p H conditions generate structures which are characterized by magnetic resonance imaging (MRI) and PGSE NMR measured dynamics
as homogeneous and heterogeneous. The data presented clearly demonstrate the applicability of the theoretical framework for
modeling hydrodynamic dispersion to the analysis of protein gels. 相似文献
8.
Colloidal particulate deposition affects the performance of industrial equipment, reverse osmosis membranes and sub-surface contaminant transport. Nuclear magnetic resonance (NMR) techniques, i.e. diffusion, diffraction and velocity imaging, are used to study the effect deposited colloidal particulate have on the fluid dynamics of water inside a model porous medium. Specially prepared oil-filled hard-sphere particles allow monitoring of particulate accumulation via NMR spectroscopy. Evidence of preferential spatial deposition is observed after the initial colloidal particulate deposition. Loss of spatial homogeneity is observed through NMR diffraction, while observations of the probability distributions of displacement (propagators) indicate the formation of back-bone type flow. This paper presents unique dynamic NMR data for the non-invasive non-destructive investigation of fluid transport in opaque porous media experiencing colloidal deposition. 相似文献
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