Magnetic resonance imaging (MRI): a technique to study flow an microstructure of concentrated emulsions

Abstract

-Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) have recently been recognized as important techniques for R&D of products and processes, as is attested by several successful applications in different areas of chemical engineering in recent years. In this article we present new experimental methods based on MRI to study flow and microstructure of concentrated emulsions. The objective is to present the unique features of this noninvasive technique to accurately measure different properties of flowing particulate opaque systems. Experimental results of velocity profiles, spatial distribution of droplet sizes and spatial homogeneity of an oil-in-water dispersion in a horizontal, concentric cylinder geometry using different pulse sequences are presented. The application of these techniques allowed probing important information on flow and microstructure of multiphase systems of interest in chemical engineering and food science.

Investigations of food colloids by NMR and MRI

“…The accuracy of the method has been widely debated for water droplet and oil droplet size determination in food emulsions such as butter, margarine and dressings [91][92][93][94]. Some extension of the method has recently been proposed for spatial determination of droplet size distribution from MRI data in emulsions [95] and to provide both real-time dispersion and spatially-resolved velocity measurements in a frozen drop of sucrose solution and emulsion [96]. However, the latter method requires the use of high field NMR spectrometers.…”

Imaging contrast effects in alginate microbeads containing trapped emulsion droplets

“…The pulse sequence is identical to the one presented in the work of d'Avila et al Fig. 2, [29]. Each image was collected with a repetition time of 2 s and an echo time of 11.5 ms.…”

Luminal Fluid Motion Inside an In Vitro Dissolution Model of the Human Ascending Colon Assessed Using Magnetic Resonance Imaging

“…MR tagging has been used to measure velocity in fluid flows, primarily in blood vessels [17] and more recently in engineering systems [18,19]. In both applications however, flows have typically been much faster than those previously measured inside the DCM (which were of the order of 2-4 cm•s −1 [22]) and mostly occurred within far smaller geometries, such as veins or nozzles, and usually with the application of only a single tag.…”

“…MR tagging velocimetry then involves the tracking of a tagged material or volume of fluid to estimate the local velocity from the displacement of tags between frames. It has been used to measure the velocity in fluid flows, primarily in blood vessels [17] and more recently in engineering systems [18,19]. Pritchard et al [20] and Wilkinson-Smith et al [16] applied an MR tagging technique to the flow of the contents of the human AC.…”