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Kaysan G, Schork N, Herberger S, Guthausen G, Kind M. Contact-mediated nucleation in melt emulsions investigated by rheo-nuclear magnetic resonance. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2022; 60:615-627. [PMID: 34700357 DOI: 10.1002/mrc.5228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
Increasing the efficiency of disperse phase crystallization is of great interest for melt emulsion production as the fraction of solidified droplets determines product quality and stability. Nucleation events must appear within every single one of the μm-sized droplets for solidification. Therefore, primary crystallization requires high subcooling and is, thus, time and energy consuming. Contact-mediated nucleation is a mechanism for intensifying the crystallization process. It is defined as the successful nucleation of a subcooled liquid droplet induced by contact with an already crystallized droplet. We investigated contact-mediated nucleation under shear flow conditions up to shear rates of 457 s-1 for a quantitative assessment of this mechanism. Rheo-nuclear magnetic resonance was successfully used for the time-resolved determination of the solids fraction of the dispersed phase of melt emulsions upon contact-mediated nucleation events. The measurements were carried out in a dedicated Taylor-Couette cell. The efficiency of contact-mediated nucleation λsec decreased with increasing shear rate, whereas the effective second order kinetic constant kcoll,eff increased approximately linearly at small shear rates and showed a linear decrease for shear rates higher than about 200 s-1 . These findings are in accordance with coalescence theory. Thus, the nucleation rate is optimal at specific flow conditions. There are limitations for successful inoculation at a low shear rate because of rare contact events and at a high shear rate due to too short contact time.
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Affiliation(s)
- Gina Kaysan
- Institute for Thermal Process Engineering, KIT, Karlsruhe, Germany
| | - Nicolas Schork
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
| | | | - Gisela Guthausen
- Institute for Mechanical Engineering and Mechanics, KIT, Karlsruhe, Germany
- Engler-Bunte Institute, Water Science and Technology, KIT, Karlsruhe, Germany
| | - Matthias Kind
- Institute for Thermal Process Engineering, KIT, Karlsruhe, Germany
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Stannarius R. Magnetic resonance imaging of granular materials. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:051806. [PMID: 28571451 DOI: 10.1063/1.4983135] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Magnetic Resonance Imaging (MRI) has become one of the most important tools to screen humans in medicine; virtually every modern hospital is equipped with a Nuclear Magnetic Resonance (NMR) tomograph. The potential of NMR in 3D imaging tasks is by far greater, but there is only "a handful" of MRI studies of particulate matter. The method is expensive, time-consuming, and requires a deep understanding of pulse sequences, signal acquisition, and processing. We give a short introduction into the physical principles of this imaging technique, describe its advantages and limitations for the screening of granular matter, and present a number of examples of different application purposes, from the exploration of granular packing, via the detection of flow and particle diffusion, to real dynamic measurements. Probably, X-ray computed tomography is preferable in most applications, but fast imaging of single slices with modern MRI techniques is unmatched, and the additional opportunity to retrieve spatially resolved flow and diffusion profiles without particle tracking is a unique feature.
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Affiliation(s)
- Ralf Stannarius
- Institute of Experimental Physics, Otto-von-Guericke-University, Universitätsplatz 2, D-39106 Magdeburg, Germany
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Kuczera S, Galvosas P. Advances and artefact suppression in RARE-velocimetry for flow with curved streamlines. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 259:135-145. [PMID: 26340434 DOI: 10.1016/j.jmr.2015.07.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 07/13/2015] [Accepted: 07/17/2015] [Indexed: 06/05/2023]
Abstract
Method and considerations are presented that allow for an improved quantitative velocity measurement of complex fluids under shear using a fast 2D PGSE-RARE technique. While this contribution is relevant for shear geometries with rotational symmetry in general, the focus here is set on cylindrical Couette cells, a device most commonly used for rheological NMR investigations. The curved nature of the flow within the shearing geometry creates challenges in accurately determining the flow profile, as conventional imaging gradients naturally operate on a Cartesian grid. In particular the appropriate slice thickness in the flow direction and the applied k-space trajectory are discussed. For the latter an MRI simulation program has been written that numerically solves the Bloch equations and allows for the investigation of out-of-pixel flow. Furthermore, we present ways of increasing the spatial resolution across the gap of cylindrical Couette cells while still providing 2D imaging capabilities under certain conditions, thus allowing for a more detailed quantification of flow profiles as necessary for the analysis of complex fluid flow.
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Affiliation(s)
- Stefan Kuczera
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand
| | - Petrik Galvosas
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
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Moucheront P, Bertrand F, Koval G, Tocquer L, Rodts S, Roux JN, Corfdir A, Chevoir F. MRI investigation of granular interface rheology using a new cylinder shear apparatus. Magn Reson Imaging 2010; 28:910-8. [DOI: 10.1016/j.mri.2010.01.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 01/09/2010] [Indexed: 10/19/2022]
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Rodts S, Boujlel J, Rabideau B, Ovarlez G, Roussel N, Moucheront P, Lanos C, Bertrand F, Coussot P. Solid-liquid transition and rejuvenation similarities in complex flows of thixotropic materials studied by NMR and MRI. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:021402. [PMID: 20365563 DOI: 10.1103/physreve.81.021402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Revised: 10/16/2009] [Indexed: 05/29/2023]
Abstract
We study the flow of a typical thixotropic material subjected to very different deformation histories (squeeze, shear, and extrusion) with either local (proton NMR and magnetic resonance imaging) or macroscopic measurements after different times of rest. Specifically, we measure the velocity fields and the spin-spin NMR relaxation of the material after different flow histories. The relaxation data exhibits a long relaxing component revealing information about the reversible microstructural evolution of the sample during aging-rejuvenation cycles. We show that for each deformation process, the evolution of the viscosity during the solid-liquid transition is similar by a factor related to the initial state of the material. Moreover, results examining the impact of the rate at which the deformation is imposed suggest that the state of the material during this transition may be described by a single parameter reflecting the average size and deformation of the material's flocs. These results also show that localization of flow occurs as a result of a progressive differential evolution of the material in different regions of the flow, and thus are determined by the boundary conditions of the flow.
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Affiliation(s)
- S Rodts
- Institut Navier, LMSGC, Université Paris-Est, 2 Allée Kepler, 77420 Champs sur Marne, France
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Bayly PV, Massouros PG, Christoforou E, Sabet A, Genin GM. Magnetic Resonance Measurement of Transient Shear Wave Propagation in a Viscoelastic Gel Cylinder. JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS 2008; 56:2036-2049. [PMID: 18568090 PMCID: PMC2435052 DOI: 10.1016/j.jmps.2007.10.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A magnetic resonance measurement technique was developed to characterize the transient mechanical response of a gel cylinder subjected to angular acceleration. The technique employs tagged magnetic resonance imaging (MRI) synchronized to periodic impact excitation of a bulk specimen. The tagged MRI sequence provides, non-invasively, an array of distributed displacement and strain measurements with high spatial (here, 5 mm) and temporal (6 ms) resolution. The technique was validated on a cylindrical gelatin sample. Measured dynamic strain fields were compared to strain fields predicted using (1) a closed-form solution and (2) finite element simulation of shear waves in a three-parameter "standard" linear viscoelastic cylinder subjected to similar initial and boundary conditions. Material parameters used in the analyses were estimated from measurements made on the gelatin in a standard rheometer. The experimental results support the utility of tagged MRI for dynamic, non-invasive assays such as measurement of shear waves in brain tissue during angular acceleration of the skull. When applied in the inverse sense, the technique has potential for characterization of the mechanical behavior of gel biomaterials.
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Affiliation(s)
- P V Bayly
- Department of Mechanical and Aerospace Engineering, Washington University, St. Louis, Missouri, 63130
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López-González MR, Holmes WM, Callaghan PT. Rheo-NMR phenomena of wormlike micelles. SOFT MATTER 2006; 2:855-869. [PMID: 32680277 DOI: 10.1039/b600978f] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Using a combination of rheology and nuclear magnetic resonance (NMR) spectroscopy/velocimetry we demonstrate the existence of shear banding fluctuations under Couette flow of the micellar system 10% w/v cetylpyridinium chloride and sodium salicylate (CPyCl-NaSal) molar ratio 2 : 1 in 0.5 M NaCl in either HO or HO, using both time-averaged and real-time measurements. These shear banding fluctuations are consistent not only with the shear stress fluctuations observed in rheological measurements but also with fluctuations in the change of the constrained fraction of the amphiphile chain (Δ) observed in H-NMR spectroscopy experiments. Using H-NMR spectroscopy on a deuterated probe molecule (-decane) located in the wormlike micellar interior, direct measurement of the shear-induced nematic phase transition is reported.
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Affiliation(s)
- M R López-González
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, New Zealand
| | - W M Holmes
- Wellcome Surgical Institute, University of Glasgow, Glasgow, United KingdomG61 1QH
| | - P T Callaghan
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, New Zealand
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Galvosas P, Callaghan PT. Fast magnetic resonance imaging and velocimetry for liquids under high flow rates. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2006; 181:119-25. [PMID: 16644252 DOI: 10.1016/j.jmr.2006.03.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Revised: 03/18/2006] [Accepted: 03/31/2006] [Indexed: 05/08/2023]
Abstract
We here demonstrate the use of NMR velocity imaging techniques to measure flow in a free falling jet of water at speeds up to and on the order of 1m/s. In particular, we show how to adapt the RARE imaging method, based on a CPMG multiple rf pulse train, so that the real and imaginary parts of the signal may be suitably acquired, enabling pulsed gradient spin echo encoding for flow. We term this method "soft-pulse-quadrature-cycled PGSE-RARE" or SPQC-PGSE-RARE. We further demonstrate the use of a one-dimensional (slice selective) imaging method which takes advantage of the cylindrical symmetry of the flow, and considerably shortens the image acquisition time.
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Affiliation(s)
- Petrik Galvosas
- MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
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Kassem H, Rodts S. Traitement de données pour la vélocimétrie RMN d'écoulement rapides : étude par simulation numérique de la mesure en rhéométrie « Couette ». CR CHIM 2006. [DOI: 10.1016/j.crci.2005.06.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Zhang X, Webb AG. Magnetic resonance microimaging and numerical simulations of velocity fields inside enlarged flow cells used for coupled NMR microseparations. Anal Chem 2005; 77:1338-44. [PMID: 15732916 PMCID: PMC2754838 DOI: 10.1021/ac048532b] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The coupling of various chemical microseparation methods with small-scale NMR detection is a growing area in analytical chemistry. The formation of enlarged flow cells within the active volume of the NMR detector can significantly increase the coil filling factor and hence the signal-to-noise ratio of the NMR spectra. However, flow cells can also lead to deterioration of the separation efficiency due to the development of complex flow patterns, the form of which depend on the particular geometry of the flow cell and the flow rate used. In this study, we investigated the flow characteristics in different flow cell geometries relevant to the coupling of capillary liquid chromatography and NMR. Computational fluid dynamics was used to simulate fluid flow inside flow cells with a volume of approximately 1 microL. Magnetic resonance microimaging was used to measure experimentally the velocity fields inside these flow cells. The results showed good agreement between experiment and simulation and demonstrated that a relatively gradual expansion and contraction is necessary to avoid areas of weak recirculation and strong radial velocities, both of which can potentially compromise separation efficiency.
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Affiliation(s)
- Xiaofeng Zhang
- Department of Electrical and Computer Engineering; and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana—Champaign, Urbana, Illinois 61801
| | - Andrew G. Webb
- Department of Electrical and Computer Engineering; and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana—Champaign, Urbana, Illinois 61801
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Manneville S, Salmon JB, Colin A. A spatio-temporal study of rheo-oscillations in a sheared lamellar phase using ultrasound. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2004; 13:197-212. [PMID: 15052429 DOI: 10.1140/epje/e2004-00046-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present an experimental study of the flow dynamics of a lamellar phase sheared in the Couette geometry. High-frequency ultrasonic pulses at 36 MHz are used to measure time-resolved velocity profiles. Oscillations of the viscosity occur in the vicinity of a shear-induced transition between a high-viscosity disordered fluid and a low-viscosity ordered fluid. The phase coexistence shows up as shear bands on the velocity profiles. We show that the dynamics of the rheological data result from two different processes: (i) fluctuations of slip velocities at the two walls and (ii) flow dynamics in the bulk of the lamellar phase. The bulk dynamics are shown to be related to the displacement of the interface between the two differently sheared regions in the gap of the Couette cell. Two different dynamical regimes are investigated under applied shear stress: one of small amplitude oscillations of the viscosity delta eta/eta approximately equal to 3%) and one of large oscillations (delta eta/eta approximately equal to 25%). A phenomenological model is proposed that may account for the observed spatio-temporal dynamics.
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Affiliation(s)
- S Manneville
- Centre de Recherche Paul Pascal, Avenue Schweitzer, 33600 Pessac, France.
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13
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Coussot P, Raynaud JS, Bertrand F, Moucheront P, Guilbaud JP, Huynh HT, Jarny S, Lesueur D. Coexistence of liquid and solid phases in flowing soft-glassy materials. PHYSICAL REVIEW LETTERS 2002; 88:218301. [PMID: 12059505 DOI: 10.1103/physrevlett.88.218301] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2001] [Indexed: 05/23/2023]
Abstract
Magnetic-resonance-imaging rheometrical experiments show that concentrated suspensions or emulsions cannot flow steadily at a uniform rate smaller than a critical value (gamma(c)). As a result, a "liquid" region (sheared rapidly, i.e., at a rate larger than gamma(c)) and a "solid" region (static) coexist. The behavior of the fluid in the liquid region follows a simple power-law model, while the extent of the solid region increases with the degree of jamming of the material.
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Affiliation(s)
- P Coussot
- LMSGC, 2 Allée Kepler, 77420 Champs sur Marne, France.
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Moser KW, Raguin LG, Harris A, Morris HD, Georgiadis J, Shannon M, Philpott M. Visualization of Taylor-Couette and spiral Poiseuille flows using a snapshot FLASH spatial tagging sequence. Magn Reson Imaging 2000; 18:199-207. [PMID: 10722980 DOI: 10.1016/s0730-725x(99)00121-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A new magnetic resonance imaging technique was applied to the Taylor-Couette and spiral Poiseuille (Taylor-Couette with superposed mean axial flux) flows for the first time. The experimental technique is a combination of spatial tagging methods and a snapshot FLASH imaging sequence, which allows the full-field visualization of 2-D slices of the flow field, with image acquisition times approximately half a second. By acquiring images every few seconds, direct visualization of flow patterns can be obtained in the form of cinematography. Tagged images of the Taylor-Couette flow were acquired in both the axial and transverse planes and confirmed previously reported numerical predictions of Taylor cell size. Tagged images of the spiral Poiseuille flows verified that the cells in this flow propagate at a higher velocity than the mean axial flow. In addition, intermittent cell formation was observed as the axial flow was increased.
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Affiliation(s)
- K W Moser
- Lab for Quantitative Visualization in Energetics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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