Pattern search methods for pendant drops: Algorithms for rapid determination of surface tension and surfactant transport parameters

White, Andrew R.; Ward, Thomas

doi:10.1016/j.colsurfa.2015.08.038

Cited by 14 publications

(8 citation statements)

References 20 publications

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“…The solid lines in Supporting Information Figure C.1 are the best fits of Eq. neglecting diffusion i.e., C s = C 0 using a two‐parameter ( β 0 and α 0 ) pattern search algorithm . We observed that the adsorption and desorption rate constants, β 0 and α 0 , apparently can vary with the initial bulk concentration C 0 raised to some exponent m. Plots of these rate constants vs. C 0 are provided in the Supporting Information Supplementary Material C in Figure C.2.…”

Section: Methodsmentioning

confidence: 93%

“…The experimental setup and procedure are described in Ref. . The continuous phases for SDS pendant drop experiments were light mineral oil (Fisher Scientific, Pittsburgh, PA, USA) ( ρ =830 kg m –3 ), heavy mineral oil (Fisher Scientific, Pittsburgh, PA, USA) ( ρ =900 kg m –3 ), and 1000 cSt polydimethysiloxane (silicone) oil (Clearco, Willow Grove, PA, USA) ( ρ =980 kg m –3 ).…”

Section: Methodsmentioning

confidence: 99%

“…Images of pendant drops were taken over time, and their change in shape was analyzed to determine the corresponding changes in surface tension . Intervals between images were 2 s for the SDS measurements; for supplemental SO, CTAB, and C 12 E 4 measurements, intervals between images were between 2 and 600 s. Drop volumes ranged from 5 to 50 μL depending on the oil phase.…”

Section: Methodsmentioning

confidence: 99%

“…The equilibrium fitting parameters Γ ∞ , K eq , and Λ were determined by fitting Eq. to equilibrium surface tension data with a three‐parameter pattern search algorithm . Equilibrium surface tension values (including supplemental C 12 E 4 –air and CTAB–heavy mineral oil data for comparison) are plotted in Figure with fits of the Frumkin isotherm and equation of state shown as solid lines.…”

Section: Methodsmentioning

confidence: 99%

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Surface remobilization of buoyancy‐driven surfactant‐laden drops at low reynolds and capillary numbers

White

Ward

2018

AIChE Journal

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It is well known that the terminal velocity of a drop settling in a viscous fluid is impacted by surface tension gradients. These gradients can develop because of nonuniform accumulation of surfactant on the surface as a result of a number of transport mechanisms. Here, a surfactant transport model based on a sorption-limited Frumkin framework is used to describe surfactant transport in the presence of both surface convection and diffusion at low Reynolds and capillary numbers. Constants characterizing surfactant transport in the Frumkin framework are experimentally determined and used to predict aqueous drop velocities with varying surfactant concentrations and volumes. Computation is carried out by satisfying equations governing mass, momentum, and interface species conservation. Experiments demonstrate qualitative and quantitative agreement between predicted and measured drop velocities. It is shown that surface remobilization explains some observed trends in measured velocity as the drop size decreases.The vertical lines are error bars representing uncertainty in drop velocity and size. The predicted drag coefficients using SDS (aq) -heavy mineral oil sorption kinetics and the boundary element method are also shown.The solid, dashed, and dotted lines are the best fits of the semi-analytical solution with D s (C 0 ) as a fitting parameter.

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Section: Methodsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Surface remobilization of buoyancy‐driven surfactant‐laden drops at low reynolds and capillary numbers

White

Ward

2018

AIChE Journal

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“…The piezoelectric cantilever density was ρ = 1800 kg/m 3 with an average elastic modulus of 3 × 10 9 GPa based on information provided by the manufacturer. Data for the damping coefficients µ 1 and µ 2 , and results of the pattern search method (White and Ward, 2015) used to find their values, appears as Supplementary…”

Section: Wind Tunnel Experiments and Governing Equationsmentioning

confidence: 99%

Experimental investigation of inclined cantilever beams in vertically falling soap films

Sajjanapu

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I dedicate this thesis to my mother, Smt. Vijaya Lakshmi without whose support, motivation and eternal love, since the beginning of my journey to the United States until now, has enabled me to accomplish this goal. I would like to thank my major professor for his support and patience in successfully achieving the research objective. Lastly, I thank my family for their loving guidance and financial assistance through out the time I spent for my masters degree.

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Matched asymptotic shock-layer analysis of the interaction between a planar viscous-hypersonic boundary layer and a thin inviscid layer

Ward

Shellabarger²,

Davis³

2022

Theor. Comput. Fluid Dyn.

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Pattern search methods for pendant drops: Algorithms for rapid determination of surface tension and surfactant transport parameters

Cited by 14 publications

References 20 publications

Surface remobilization of buoyancy‐driven surfactant‐laden drops at low reynolds and capillary numbers

Surface remobilization of buoyancy‐driven surfactant‐laden drops at low reynolds and capillary numbers

Experimental investigation of inclined cantilever beams in vertically falling soap films

Matched asymptotic shock-layer analysis of the interaction between a planar viscous-hypersonic boundary layer and a thin inviscid layer

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