Mixing within drops via surface shear viscosity

Gulati, Shreyash; Riley, Frank; Lopez, Juan M.; Hirsa, Amir

doi:10.1016/j.ijheatmasstransfer.2018.04.057

Cited by 9 publications

(6 citation statements)

References 35 publications

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“…At this maximum distance in the x-direction (or identically when ∂ x/∂t = ∂ x px /∂t = 0), the exact position of the particle in 3D space is known. Subsequently, assuming constant radial position (that the radial velocity component is much smaller than the primary azimuthal velocity component, ∂ r/∂t → 0, (Gulati et al, 2019(Gulati et al, , 2018)) allows single-camera determination of 3D particle position in all frames. Depth determination requires calculation of where an individual ray intersects the surface of a sphere of radius r (r defined above as the maximum x-direction path distance).…”

Section: Depth Determinationmentioning

confidence: 99%

“…1). (Gulati et al, 2017(Gulati et al, , 2019(Gulati et al, , 2018McMackin et al, , 2020Riley et al, 2021) The original investigation (2019 and 2021 ISS flight campaigns) of the RSD focused on the effects of interfacial shear on the fibrillization kinetics (amyloidogenesis) of human insulin, centering on flow's effect on the biological system. However, changes in the biological system also produce reciprocal changes in fluid flow.…”

Section: Introductionmentioning

confidence: 99%

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Single-camera PTV within interfacially sheared drops in microgravity

McMackin,

Adam,

Riley

et al. 2023

Exp Fluids

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Development of experimental methods for in situ particle tracking velocimetry (PTV) is fundamental for allowing measurement of moving systems nontailored for velocimetry. This investigation focuses on the development of a post-processing methodology for single-camera PTV, without laser-sheet illumination, tracking native air-bubbles as tracer particles within a liquid drop of human insulin in microgravity. This PTV scenario was facilitated by microgravity technology known as the ring-sheared drop (RSD), aboard the International Space Station, which produced an optical imaging scenario and fluid flow geometry suitable as a testbed for PTV research. The post processing methodology performed included five steps: (i) physical system characterization and native air-bubble tracer identification, (ii) image projection and single-camera calibration, (iii) depth determination and 3D particle position determination, (iv) ray tracing and refraction correction, and (v) particle history and dataIn situ PTV in sheared drops expansion for suboptimal particles. Overall, this post processing methodology successfully allowed for a total of 1,085 particle measurements in a scenario where none were previously possible. Such post processing methodologies have promise for application to other in situ PTV scenarios allowing better understanding of physical systems whose flow is difficult to measure and or where PTV-specific optical elements (such as laser lights sheets and dual camera setups) are not permissible due to physical or safety constraints.

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Section: Depth Determinationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single-camera PTV within interfacially sheared drops in microgravity

McMackin,

Adam,

Riley

et al. 2023

Exp Fluids

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“…One of the rings rotates while the other is held stationary. This differential rotation produces shearing of the interface which in turn drives flow and mixing in the bulk through the action of surface shear viscosity 15 . The RSD technology was developed to study the formation of protein amyloid fibrils, which play a central role in many neurodegenerative disorders including Alzheimer's disease and Parkinson's 16 .…”

Section: Introductionmentioning

confidence: 99%

“…The RSD technology was developed to study the formation of protein amyloid fibrils, which play a central role in many neurodegenerative disorders including Alzheimer's disease and Parkinson's 16 . The RSD offers several fundamental advantages over previous concepts for spaced-based bioreactors: (i) readily scalable-functions with volumes <1 mL to about 1000 mL, (ii) no barriers to gas exchange-virtually the entire surface is free, (iii) no barriers to light transmission-by virtue of not having solid walls, there is no need for optical windows that can be fouled, (iv) energy efficient mixing-due to the fact that mixing in the bulk is conveyed by surface shear viscosity, and finally (v) low reactor weight-since there is no solid container 15,17 .…”

Section: Introductionmentioning

confidence: 99%

Growth of microorganisms in an interfacially driven space bioreactor analog

et al. 2020

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Fluid bioreactors in microgravity environments may utilize alternative methods of containment and mixing. The ring-sheared drop (RSD) is a containerless mixing device which functions in microgravity using surface tension for containment and mixes through interfacially-driven flow. To assess the feasibility of using interfacially driven flow devices, such as the RSD, as bioreactors, Escherichia coli growth and recombinant protein expression were analyzed in a ground-based analog of the RSD called the knife edge surface viscometer (KEV). Results demonstrated that the KEV can facilitate the growth of E. coli and that growth rate increases logarithmically with increasing knife edge rotation rate, similar to the standard growth method on Earth (orbital shaker). Furthermore, the KEV was shown to be viable for supporting recombinant protein expression in E. coli at levels comparable to those achieved using standard growth methods.npj Microgravity (2020) 6:11 ; https://doi.

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“…Two subsequent studies, both computational and without gravity, have reported on the flow in a spherical drop that is sheared by sharp-edged contact rings. Specifically, Gulati et al 12 presented numerical simulations of the flow in the RSD and its implications on mixing within the drop. For that study, the surface shear viscosity was assumed to be large compared to the product of the viscosity in the bulk, , and the drop radius, .…”

Section: Introductionmentioning

confidence: 99%

Simulated microgravity in the ring-sheared drop

et al. 2020

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The ring-sheared drop is a module for the International Space Station to study sheared fluid interfaces and their influence on amyloid fibril formation. A 2.54-cm diameter drop is constrained by a stationary sharp-edged ring at some latitude and sheared by the rotation of another ring in the other hemisphere. Shearing motion is conveyed primarily by the action of surface shear viscosity. Here, we simulate microgravity in the laboratory using a density-matched liquid surrounding the drop. Upon shearing, the drop’s deformation away from spherical is found to be a result of viscous and inertial forces balanced against the capillary force. We also present evidence that the deformation increases with increasing surface shear viscosity.

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Mixing within drops via surface shear viscosity

Cited by 9 publications

References 35 publications

Single-camera PTV within interfacially sheared drops in microgravity

Single-camera PTV within interfacially sheared drops in microgravity

Growth of microorganisms in an interfacially driven space bioreactor analog

Simulated microgravity in the ring-sheared drop

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