Eric S.G. Shaqfeh
Lester Levi Carter Professor and Professor of Mechanical Engineering
Chemical Engineering
Bio
Eric Shaqfeh is the Lester Levi Carter Professor of Chemical Engineering at Stanford University. He earned a B.S.E. summa cum laude from Princeton University (1981), and a M.S. (1982) and Ph.D. (1986) from Stanford University all in Chemical Engineering. In 1986, he was a NATO postdoctoral fellow at the Department of Applied Mathematics and Theoretical Physics at the University of Cambridge. From 1987 through 1989 he was employed as a Member of Technical Staff at AT&T Bell Laboratories in Murray Hill, NJ before joining the Stanford Chemical Engineering faculty in early 1990. In 2001 he received a dual appointment and became Professor of Mechanical Engineering. He is most recently (as of 2004) a faculty member in the Institute of Computational and Mathematical Engineering at Stanford.
Shaqfeh’s current research interests include non-Newtonian fluid mechanics (especially in the area of elastic instabilities, and turbulent drag reduction), nonequilibrium polymer statistical dynamics (focusing on single molecules studies of DNA), and suspension mechanics (particularly of fiber suspensions and particles/vesicles in microfluidics). He has authored or co-authored over 200 publications and has been an Associate Editor of the Physical Review Fluids since 2016.
Shaqfeh has received the APS Francois N. Frenkiel Award 1989, the NSF Presidential Young Investigator Award 1990, the David and Lucile Packard Fellowship in Science and Engineering 1991, the Camile and Henry Dreyfus Teacher--Scholar Award 1994, the W.M. Keck Foundation Engineering Teaching Excellence Award 1994, the 1998 ASEE Curtis W. McGraw Award,the 2011 Bingham Medal from the Society of Rheology, and the 2018 Alpha Chi Sigma Award from the AICHE. A Fellow of the American Physical Society (2001) and a member of the National Academy of Engineering(2013), he has held a number of professional lectureships, most recently the Merck Distinguished Lectureship, Rutgers (2003), the Corrsin Lectureship, Johns Hopkins (2003) and the Katz Lectureship, CCNY (2004). He was also the Hougen Professor of Chemical Engineering at the University of Wisconsin (2004) and the Probstein Lecturer at MIT (2011).
Academic Appointments
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Professor, Chemical Engineering
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Professor, Mechanical Engineering
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Member, Bio-X
Honors & Awards
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Elmer Gaden Lecture, Columbia University (2022)
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William Schowalter Lectureship, Americal Institute of Chemical Engineering (2021)
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Fellow, AICHE (2019)
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Alpha Chi Sigma Award, American Institute of Chemical Engineering (2018)
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Editorial Board, Physical Review Fluids (2016-present)
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Member, National Academy of Engineering (2013-present)
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Lester Levi Carter Endowed Professorship, Stanford University (2011-present)
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E.C. Bingham Medal (for Outstanding Contributions to Rheology), Society of Rheology (2011)
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Ronald Probstein Lecturer in Engineering Science, MIT (2011)
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Hougen Professor, Department of Chemical Engineering, University of Wisconsin (2004)
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Stanley Corrsin Lectureship, Department of Chemical and Biomolecular Engineering, Johns Hopkins University (2003)
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Van Ness Lectureship, Department of Chemical Engineering, Rensselaer Polytechnic Institute (2001)
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Fellow, American Physical Society (2000)
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Curtis W. McGraw Research Award, American Society of Engineering Education (1998)
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David and Lucile Packard Fellow in Science and Engineering, Stanford University (1991-96)
Professional Education
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BS, Princeton University, Chemical Engineering (and Engineering Physics) (1981)
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MS, Stanford University, Chemical Engineering (1982)
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PhD, Stanford University, Chemical Engineering (1986)
Current Research and Scholarly Interests
I have over 25 years experience in theoretical and computational research related to complex fluids following my PhD in 1986. This includes work in suspension mechanics of rigid partlcles (rods), solution mechanics of polymers and most recently suspensions of vesicles, capsules and mixtures of these with rigid particles. My research group is internationally known for pioneering work in all these areas.
2024-25 Courses
- Applied Mathematics in the Chemical and Biological Sciences
CHEMENG 300, CME 330 (Aut) - Microhydrodynamics
CHEMENG 310, ME 451D (Win) -
Independent Studies (14)
- Engineering Problems
ME 391 (Aut, Win, Spr) - Engineering Problems and Experimental Investigation
ME 191 (Aut, Win, Spr) - Experimental Investigation of Engineering Problems
ME 392 (Aut, Win, Spr) - Graduate Research in Chemical Engineering
CHEMENG 600 (Aut, Win, Spr) - Honors Research
ME 191H (Aut, Win, Spr) - Master's Directed Research
ME 393 (Aut, Win, Spr) - Master's Directed Research: Writing the Report
ME 393W (Aut, Win, Spr) - Ph.D. Research Rotation
ME 398 (Aut, Win, Spr) - Ph.D. Teaching Experience
ME 491 (Aut, Win, Spr) - Practical Training
ME 199A (Win, Spr) - Practical Training
ME 299A (Aut, Win, Spr) - Practical Training
ME 299B (Aut, Win, Spr) - Undergraduate Honors Research in Chemical Engineering
CHEMENG 190H (Aut, Win, Spr) - Undergraduate Research in Chemical Engineering
CHEMENG 190 (Aut, Win, Spr)
- Engineering Problems
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Prior Year Courses
2023-24 Courses
- Applied Mathematics in the Chemical and Biological Sciences
CHEMENG 300, CME 330 (Aut) - Microhydrodynamics
CHEMENG 310, ME 451D (Win)
2022-23 Courses
- Applied Mathematics in the Chemical and Biological Sciences
CHEMENG 300, CME 330 (Aut) - Microhydrodynamics
CHEMENG 310, ME 451D (Spr) - Partial Differential Equations in Engineering
CME 204, ME 300B (Win) - Special Topics in Transport Mechanics
CHEMENG 510 (Aut)
2021-22 Courses
- Partial Differential Equations in Engineering
CME 204, ME 300B (Win) - Seminar in Fluid Mechanics
ENGR 298 (Spr) - Special Topics in Transport Mechanics
CHEMENG 510 (Aut, Win, Spr, Sum)
- Applied Mathematics in the Chemical and Biological Sciences
Stanford Advisees
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Doctoral Dissertation Advisor (AC)
Zach Zajo -
Master's Program Advisor
Andrea Beltran Lopez, Nico Brouhard, Kara Dane, Stephen Han, Patrick Harney, Jason Herritt, Edward Hsieh, Dominic LaJoie, Romain Lacombe, Samantha Li, Patricia Liang, Wyatt Liao, Nick Meyer, Fern Morrison, Hoda Nahhas, Nathan Nguyen, Phuong Nguyen, Alexander Razaghi, Albert Thai, Clark Wey, Jonathan Yeung -
Doctoral Dissertation Co-Advisor (AC)
Selena Chiu, Nicholas Dorn, Gabriel Lipkowitz, Cody Moose, Vedika Shenoy -
Doctoral (Program)
Anjini Chandra, Kunlin Ma, Cody Moose
All Publications
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High-resolution stereolithography: Negative spaces enabled by control of fluid mechanics.
Proceedings of the National Academy of Sciences of the United States of America
2024; 121 (37): e2405382121
Abstract
Stereolithography enables the fabrication of three-dimensional (3D) freeform structures via light-induced polymerization. However, the accumulation of ultraviolet dose within resin trapped in negative spaces, such as microfluidic channels or voids, can result in the unintended closing, referred to as overcuring, of these negative spaces. We report the use of injection continuous liquid interface production to continuously displace resin at risk of overcuring in negative spaces created in previous layers with fresh resin to mitigate the loss of Z-axis resolution. We demonstrate the ability to resolve 50-μm microchannels, breaking the historical relationship between resin properties and negative space resolution. With this approach, we fabricated proof-of-concept 3D free-form microfluidic devices with improved design freedom over device material selection and resulting properties.
View details for DOI 10.1073/pnas.2405382121
View details for PubMedID 39231205
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Growing three-dimensional objects with light.
Proceedings of the National Academy of Sciences of the United States of America
2024; 121 (28): e2303648121
Abstract
Vat photopolymerization (VP) additive manufacturing enables fabrication of complex 3D objects by using light to selectively cure a liquid resin. Developed in the 1980s, this technique initially had few practical applications due to limitations in print speed and final part material properties. In the four decades since the inception of VP, the field has matured substantially due to simultaneous advances in light delivery, interface design, and materials chemistry. Today, VP materials are used in a variety of practical applications and are produced at industrial scale. In this perspective, we trace the developments that enabled this printing revolution by focusing on the enabling themes of light, interfaces, and materials. We focus on these fundamentals as they relate to continuous liquid interface production (CLIP), but provide context for the broader VP field. We identify the fundamental physics of the printing process and the key breakthroughs that have enabled faster and higher-resolution printing, as well as production of better materials. We show examples of how in situ print process monitoring methods such as optical coherence tomography can drastically improve our understanding of the print process. Finally, we highlight areas of recent development such as multimaterial printing and inorganic material printing that represent the next frontiers in VP methods.
View details for DOI 10.1073/pnas.2303648121
View details for PubMedID 38950359
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Stresslet in a dilute suspension of rigid spheres in an Oldroyd-B fluid
PHYSICAL REVIEW FLUIDS
2024; 9 (3)
View details for DOI 10.1103/PhysRevFluids.9.033301
View details for Web of Science ID 001187514700002
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The effects of suspending fluid viscoelasticity on the mechanical properties of capsules and red blood cells in flow
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2024; 326
View details for DOI 10.1016/j.jnnfm.2024.105215
View details for Web of Science ID 001199423100001
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Methods for modeling and real-time visualization of CLIP and iCLIP-based 3D printing
GIANT
2024; 17
View details for DOI 10.1016/j.giant.2024.100239
View details for Web of Science ID 001167580600001
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Designing a swimming rheometer to measure the linear and non-linear properties of a viscoelastic fluid
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2023; 322
View details for DOI 10.1016/j.jnnfm.2023.105151
View details for Web of Science ID 001125219400001
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Rheology of non-Brownian particle suspensions in viscoelastic solutions. Part II: Effect of a shear thinning suspending fluid
JOURNAL OF RHEOLOGY
2023; 67 (2): 517-540
View details for DOI 10.1122/8.0000541
View details for Web of Science ID 000933034000002
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Rheology of non-Brownian particle suspensions in viscoelastic solutions. Part 1: Effect of the polymer concentration
JOURNAL OF RHEOLOGY
2023; 67 (2): 499-516
View details for DOI 10.1122/8.0000540
View details for Web of Science ID 000933034000001
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Palete-PrintAR: an augmented reality fluidic design tool for multicolor resin 3D printing
ASSOC COMPUTING MACHINERY. 2023
View details for DOI 10.1145/3586182.3616684
View details for Web of Science ID 001125107000046
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Printing atom-efficiently: faster fabrication of farther unsupported overhangs by fluid dynamics simulation
ASSOC COMPUTING MACHINERY. 2023
View details for DOI 10.1145/3623263.3623354
View details for Web of Science ID 001147521200011
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Instability and symmetry breaking of surfactant films over an air bubble
JOURNAL OF FLUID MECHANICS
2022; 953
View details for DOI 10.1017/jfm.2022.888
View details for Web of Science ID 000895812600001
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Single-digit-micrometer-resolution continuous liquid interface production.
Science advances
2022; 8 (46): eabq2846
Abstract
To date, a compromise between resolution and print speed has rendered most high-resolution additive manufacturing technologies unscalable with limited applications. By combining a reduction lens optics system for single-digit-micrometer resolution, an in-line camera system for contrast-based sharpness optimization, and continuous liquid interface production (CLIP) technology for high scalability, we introduce a single-digit-micrometer-resolution CLIP-based 3D printer that can create millimeter-scale 3D prints with single-digit-micrometer-resolution features in just a few minutes. A simulation model is developed in parallel to probe the fundamental governing principles in optics, chemical kinetics, and mass transport in the 3D printing process. A print strategy with tunable parameters informed by the simulation model is adopted to achieve both the optimal resolution and the maximum print speed. Together, the high-resolution 3D CLIP printer has opened the door to various applications including, but not limited to, biomedical, MEMS, and microelectronics.
View details for DOI 10.1126/sciadv.abq2846
View details for PubMedID 36383664
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Injection continuous liquid interface production of 3D objects.
Science advances
2022; 8 (39): eabq3917
Abstract
In additive manufacturing, it is imperative to increase print speeds, use higher-viscosity resins, and print with multiple different resins simultaneously. To this end, we introduce a previously unexplored ultraviolet-based photopolymerization three-dimensional printing process. The method exploits a continuous liquid interface-the dead zone-mechanically fed with resin at elevated pressures through microfluidic channels dynamically created and integral to the growing part. Through this mass transport control, injection continuous liquid interface production, or iCLIP, can accelerate printing speeds to 5- to 10-fold over current methods such as CLIP, can use resins an order of magnitude more viscous than CLIP, and can readily pattern a single heterogeneous object with different resins in all Cartesian coordinates. We characterize the process parameters governing iCLIP and demonstrate use cases for rapidly printing carbon nanotube-filled composites, multimaterial features with length scales spanning several orders of magnitude, and lattices with tunable moduli and energy absorption.
View details for DOI 10.1126/sciadv.abq3917
View details for PubMedID 36170357
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Perspectives on viscoelastic flow instabilities and elastic turbulence
PHYSICAL REVIEW FLUIDS
2022; 7 (8)
View details for DOI 10.1103/PhysRevFluids.7.080701
View details for Web of Science ID 000863183400006
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A freely suspended robotic swimmer propelled by viscoelastic normal stresses
JOURNAL OF FLUID MECHANICS
2022; 944
View details for DOI 10.1017/jfm.2022.485
View details for Web of Science ID 000817205500001
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<p>The Oldroyd-B fluid in elastic instabilities, turbulence and particle suspensions (vol 298, 104672, 2021)</p>
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2022; 304
View details for DOI 10.1016/j.jnnfm.2022.104791
View details for Web of Science ID 000793207900001
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The Oldroyd-B fluid in elastic instabilities, turbulence and particle suspensions
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2021; 298
View details for DOI 10.1016/j.jnnfm.2021.104672
View details for Web of Science ID 000715756100002
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Transient and steady shear rheology of particle-laden viscoelastic suspensions
JOURNAL OF RHEOLOGY
2021; 65 (6): 1269-1295
View details for DOI 10.1122/8.0000265
View details for Web of Science ID 000697157800002
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A theory for the coexistence of coiled and stretched configurational phases in the extensional flow of entangled polymer melts.
The Journal of chemical physics
2021; 154 (20): 204907
Abstract
It has recently been demonstrated via nonequilibrium molecular dynamics (NEMD) simulation [M. H. Nafar Sefiddashti, B. J. Edwards, and B. Khomami, J. Chem. Phys. 148, 141103 (2018); Phys. Rev. Lett. 121, 247802 (2018)] that the extensional flow of entangled polymer melts can engender, within a definite strain-rate regime [expressed in terms of the Deborah number (De) based on the Rouse time], the coexistence of separate domains consisting primarily of either coiled or stretched chain-like macromolecules. This flow-induced phase separation results in bimodal configurational distributions, where transitions of individual molecules between the coiled and stretched states occur very slowly by hopping over an apparent energy activation barrier. We demonstrate that the qualitative aspects of this phenomenon can be described via the single-mode Rolie-Poly model including Convective Constraint Release (CCR) and finite extensibility of the chain-like macromolecules. This analysis reveals the physical mechanism for the configurational coexistence, namely, the nonlinear rate of change of the average entropic restoring force of a given entangled chain with extension. Under conditions of significant flow-induced disentanglement, the rate of change of the effective restoring force initially decreases with extension (effective spring softening) and then increases (hardens) as the maximum chain length is approached. When balanced by flow-induced chain stretching, we find that there can be two configuration states within the same De regime, as covered by the NEMD simulations; therefore, a region of conformational coexistence can indeed exist. However, we demonstrate that this coexistence of configurational microstates is only possible when the magnitude of the CCR parameters is consistent with the rate of flow-induced disentanglement, as observed in the NEMD simulations.
View details for DOI 10.1063/5.0047467
View details for PubMedID 34241150
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Self-propulsion of a freely suspended swimmer by a swirling tail in a viscoelastic fluid
PHYSICAL REVIEW FLUIDS
2021; 6 (5)
View details for DOI 10.1103/PhysRevFluids.6.053301
View details for Web of Science ID 000652862200001
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Instability and symmetry breaking in binary evaporating thin films over a solid spherical dome
JOURNAL OF FLUID MECHANICS
2021; 915
View details for DOI 10.1017/jfm.2021.136
View details for Web of Science ID 000627900300001
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Squirmers with swirl at low Weissenberg number
JOURNAL OF FLUID MECHANICS
2021; 911
View details for DOI 10.1017/jfm.2020.987
View details for Web of Science ID 000611234500001
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Swimming with swirl in a viscoelastic fluid
JOURNAL OF FLUID MECHANICS
2020; 900
View details for DOI 10.1017/jfm.2020.456
View details for Web of Science ID 000559365200001
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Lift and drag force on a spherical particle in a viscoelastic shear flow (vol 280, 104279, 2020)
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2020; 282
View details for DOI 10.1016/j.jnnfm.2020.104323
View details for Web of Science ID 000558832800011
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Collective effects in the sedimentation of particles in a viscoelastic fluid
PHYSICAL REVIEW FLUIDS
2020; 5 (7)
View details for DOI 10.1103/PhysRevFluids.5.073301
View details for Web of Science ID 000551012400001
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Lift and drag force on a spherical particle in a viscoelastic shear flow
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2020; 280
View details for DOI 10.1016/j.jnnfm.2020.104279
View details for Web of Science ID 000533631500002
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Extravasation of PEGylated Spherical Nanoparticles through a Circular Pore of Similar Size
MACROMOLECULES
2020; 53 (8): 2991–3006
View details for DOI 10.1021/acs.macromol.0c00187
View details for Web of Science ID 000529885700025
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Oscillatory spontaneous dimpling in evaporating curved thin films
JOURNAL OF FLUID MECHANICS
2020; 889
View details for DOI 10.1017/jfm.2020.92
View details for Web of Science ID 000515191000001
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A system for the high-throughput measurement of the shear modulus distribution of human red blood cells.
Lab on a chip
2020
Abstract
Reduced deformability of red blood cells (RBCs) can affect the hemodynamics of the microcirculation and reduce oxygen transport efficiency. It is also well known that reduced RBC deformability is a signature of various physical disorders, including sepsis, and that the primary determinant of RBC deformability is the membrane shear modulus. To measure the distribution of an individual's RBC shear modulus with high throughput, we a) developed a high-fidelity computational model of RBCs in confined microchannels to inform design decisions; b) created a novel experimental system combining microfluidic flow, imaging, and image analysis; and c) performed automated comparisons between measured quantities and numerical predictions to extract quantitative measures of the RBC shear modulus for each of thousands of cells. We applied our computational simulation platform to construct the appropriate deformability figure(s) of merit to quantify RBC stiffness based on an experimentally measured, steady-state cell shape in flow through a microchannel. In particular, we determined a shape parameter based on the second moment of the cell shape that is sensitive to the changes in the membrane stiffness and cell size. We then conducted microfluidic experiments and developed custom automated image processing codes to identify and track the position and shape of individual RBCs within micro-constrictions. The fabricated microchannels include a square cross-section imaging region (7 by 7 μm) and we applied order 10 kPa pressure differences to induce order 10 mm s-1 cell velocities. The combination of modeling, microfluidics, and imaging enables, for the first time, quantitative measurement of the shear moduli of thousands of RBCs in human blood samples. We demonstrate the high-throughput features by sensitive quantification of the changes in the distribution of RBC stiffness with aging. This combined measurement and computational platform is ultimately intended to diagnose blood cell disorders in patients.
View details for DOI 10.1039/d0lc00283f
View details for PubMedID 32648561
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Correction: A system for the high-throughput measurement of the shear modulus distribution of human red blood cells.
Lab on a chip
2020
Abstract
Correction for 'A system for the high-throughput measurement of the shear modulus distribution of human red blood cells' by Amir Saadat et al., Lab Chip, 2020, 20, 2927-2936, DOI: 10.1039/D0LC00283F.
View details for DOI 10.1039/d0lc90126a
View details for PubMedID 33232426
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The rheology of soft bodies suspended in the simple shear flow of a viscoelastic fluid
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2019; 273
View details for DOI 10.1016/j.jnnfm.2019.104183
View details for Web of Science ID 000503909000007
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Extensional rheology of a dilute particle-laden viscoelastic solution
PHYSICAL REVIEW FLUIDS
2019; 4 (9)
View details for DOI 10.1103/PhysRevFluids.4.091301
View details for Web of Science ID 000485204200001
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Simulation of microparticle inhalation in rhesus monkey airways
PHYSICAL REVIEW FLUIDS
2019; 4 (8)
View details for DOI 10.1103/PhysRevFluids.4.083101
View details for Web of Science ID 000480243600001
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Drag coefficient for a sedimenting and rotating sphere in a viscoelastic fluid
PHYSICAL REVIEW FLUIDS
2019; 4 (6)
View details for DOI 10.1103/PhysRevFluids.4.063302
View details for Web of Science ID 000470897400001
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On the rheology of particle suspensions in viscoelastic fluids
AICHE JOURNAL
2019; 65 (5)
View details for DOI 10.1002/aic.16575
View details for Web of Science ID 000467981300024
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Blood group alters platelet binding kinetics to von Willebrand factor and consequently platelet function
BLOOD
2019; 133 (12): 1371–77
View details for DOI 10.1182/blood-2018-06-855528
View details for Web of Science ID 000461906600016
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In Vitro Measurement and Modeling of Platelet Adhesion on VWF-Coated Surfaces in Channel Flow
BIOPHYSICAL JOURNAL
2019; 116 (6): 1136–51
View details for DOI 10.1016/j.bpj.2019.01.040
View details for Web of Science ID 000461645500017
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Evaporation-driven solutocapillary flow of thin liquid films over curved substrates
PHYSICAL REVIEW FLUIDS
2019; 4 (3)
View details for DOI 10.1103/PhysRevFluids.4.034002
View details for Web of Science ID 000461075500001
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Taylor dispersion in the presence of cross flow and interfacial mass transfer
PHYSICAL REVIEW FLUIDS
2019; 4 (3)
View details for DOI 10.1103/PhysRevFluids.4.034501
View details for Web of Science ID 000460678600001
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InVitro Measurement and Modeling of Platelet Adhesion on VWF-Coated Surfaces in Channel Flow.
Biophysical journal
2019
Abstract
The process of platelet adhesion is initiated by glycoprotein (GP)Ib and GPIIbIIIa receptors on the platelet surface binding with von Willebrand factor on the vascular walls. This initial adhesion and detachment of a single platelet is a complex process that involves multiple bonds forming and breaking and is strongly influenced by the surrounding blood-flow environment. In addition to bond-level kinetics, external factors such as shear rate, hematocrit, and GPIb and GPIIbIIIa receptor densities have also been identified as influencing the platelet-level rate constants in separate studies, but this still leaves a gap in understanding between these two length scales. In this study, we investigate the fundamental relationship of the dynamics of platelet adhesion, including these interrelating factors, using a coherent strategy. We build a, to our knowledge, novel and computationally efficient multiscale model accounting for multibond kinetics and hydrodynamic effects due to the flow of a cellular suspension. The model predictions of platelet-level kinetics are verified by our microfluidic experiments, which systematically investigate the role of each external factor on platelet adhesion in an invitro setting. We derive quantitative formulas describing how the rates of platelet adhesion, translocation, and detachment are defined by the molecular-level kinetic constants, the local platelet concentration near the reactive surface determined by red-blood-cell migration, the platelet effective reactive area due to its tumbling motion, and the platelet surface receptor density. Furthermore, if any of these aspects involved have abnormalities, e.g., in a disease condition, our findings also have clinical relevance in predicting the resulting change in the adhesion dynamics, which is essential to hemostasis and thrombosis.
View details for PubMedID 30824114
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Blood group alters platelet binding kinetics to von Willebrand Factor and consequently platelet function.
Blood
2019
Abstract
Blood Type O is associated with a lower risk of myocardial infarction. Platelets play a critical role in myocardial infarction. It is not known whether the expression of blood group antigens on platelet proteins alters platelet function; we hypothesized that platelet function would be different between donors with blood type O and those with non-O. To address this hypothesis, we perfused blood from healthy type O donors (n=33) or non-O donors (n=54) over pooled plasma derived von Willebrand factor (VWF) protein and purified blood-type-specific VWF at arterial shear and measured platelet translocation dynamics. We demonstrate for the first time that type O platelets travel further at greater speeds before forming stable bonds with VWF. To further characterize these findings, we used a novel analytical model of platelet interaction. Modelling revealed that the kinetics for GPIb / VWF binding rate are significantly lower for type O compared to non-O platelets. Our results demonstrate that platelets from type O donors interact less with VWF at arterial shear than non-O platelets. Our results suggest a potential mechanism for the reduced risk of myocardial infarction associated with blood type O.
View details for PubMedID 30642918
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Three-dimensional simulations of undulatory and amoeboid swimmers in viscoelastic fluids.
Soft matter
2019
Abstract
Microorganisms often move through viscoelastic environments, as biological fluids frequently have a rich microstructure owing to the presence of large polymeric molecules. Research on the effect of fluid elasticity on the swimming kinematics of these organisms has usually been focused on those that move via cilia or flagellum. Experimentally, Shen (X. N. Shen et al., Phys. Rev. Lett., 2011, 106, 208101) reported that the nematode C. elegans, a model organism used to study undulatory motion, swims more slowly as the Deborah number describing the fluid's elasticity is increased. This phenomenon has not been thoroughly studied via a fully resolved three-dimensional simulation; moreover, the effect of fluid elasticity on the swimming speed of organisms moving via euglenoid movement, such as E. gracilis, is completely unknown. In this study, we discuss the simulation of the arbitrary motion of an undulating or pulsating swimmer that occupies finite volume in three dimensions, with the ability to specify any differential viscoelastic rheological model for the surrounding fluid. To accomplish this task, we use a modified version of the Immersed Finite Element Method presented in a previous paper by Guido and Saadat in 2018 (A. Saadat et al., Phys. Rev. E, 2018, 98, 063316). In particular, this version allows for the simulation of deformable swimmers such that they evolve through an arbitrary set of specified shapes via a conformation-driven force. From our analysis, we observe several key trends not found in previous two-dimensional simulations or theoretical analyses for C. elegans, as well as novel results for the amoeboid motion. In particular, we find that regions of high polymer stress concentrated at the head and tail of the swimming C. elegans are created by strong extensional flow fields and are associated with a decrease in swimming speed for a given swimming stroke. In contrast, in two dimensions these regions of stress are commonly found distributed along the entire body, likely owing to the lack of a third dimension for polymer relaxation. A comparison of swim speeds shows that the calculations in two-dimensional simulations result in an over-prediction of the speed reduction. We believe that our simulation tool accurately captures the swimming motion of the two aforementioned model swimmers and furthermore, allows for the simulation of multiple deformable swimmers, as well as more complex swimming geometries. This methodology opens many new possibilities for future studies of swimmers in viscoelastic fluids.
View details for DOI 10.1039/c8sm02518e
View details for PubMedID 31155624
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Immersed-finite-element method for deformable particle suspensions in viscous and viscoelastic media
PHYSICAL REVIEW E
2018; 98 (6)
View details for DOI 10.1103/PhysRevE.98.063316
View details for Web of Science ID 000454635700007
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Pressure-driven flow of a vesicle through a square microchannel
JOURNAL OF FLUID MECHANICS
2018; 861: 447–83
View details for DOI 10.1017/jfm.2018.887
View details for Web of Science ID 000454407300001
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Mechanism of shear thickening in suspensions of rigid spheres in Boger fluids. Part I: Dilute suspensions
JOURNAL OF RHEOLOGY
2018; 62 (6): 1363–77
View details for DOI 10.1122/1.5024696
View details for Web of Science ID 000449684700005
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Mechanism of shear thickening in suspensions of rigid spheres in Boger fluids. Part II: Suspensions at finite concentration
JOURNAL OF RHEOLOGY
2018; 62 (6): 1379–96
View details for DOI 10.1122/1.5024698
View details for Web of Science ID 000449684700006
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Extravasation of Brownian Spheroidal Nanoparticles through Vascular Pores
BIOPHYSICAL JOURNAL
2018; 115 (6): 1103–15
View details for DOI 10.1016/j.bpj.2018.07.038
View details for Web of Science ID 000444925400015
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Extravasation of Brownian Spheroidal Nanoparticles through Vascular Pores.
Biophysical journal
2018
Abstract
In modern cancer treatment, there is significant interest in studying the use of drug molecules either directly injected into the bloodstream or delivered by nanoparticle (NP) carriers of various shapes and sizes. During treatment, these carriers may extravasate through pores in the tumor vasculature that form during angiogenesis. We provide an analytical, computational, and experimental examination of the extravasation of point particles (e.g., drug molecules) and finite-sized spheroidal particles. We study the advection-diffusion process in a model microvasculature, consisting of a shear flow over and a pressure-driven suction flow into a circular pore in a flat surface. For point particles, we provide an analytical formula [Formula: see text] for the dimensionless Sherwood number S, i.e., the extravasation rate, in terms of the pore entry resistance (Damkohler number kappa), the shear rate (Peclet number P), and the suction flow rate (suction strength Q). Brownian dynamics (BD) simulations verify this result, and our simulations are then extended to include finite-sized NPs, in which no analytical solutions are available. BD simulations indicate that particles of different geometries have drastically different extravasation rates in different flow conditions. In general, extreme aspect ratio particles provide a greater flux through the pore because of favorable alignment with streamlines entering the pore and less hindered interaction with the pore. We validate the BD simulations by measuring the invitro transport of both bacteriophage MS2 (a spherical NP) and free dye (a model drug molecule) across a porous membrane. Despite their vastly different sizes, BD predicts S= 8.53 E-4 and S= 27.6 E-4, and our experiments agree favorably, with Sexp=10.6 E-4± 1.75 E-4 and Sexp=16.3 E-4 ± 3.09 E-4, for MS2 and free dye, respectively, thus demonstrating the practical utility of our simulation framework.
View details for PubMedID 30201266
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Stokes flow of vesicles in a circular tube
JOURNAL OF FLUID MECHANICS
2018; 851: 606–35
View details for DOI 10.1017/jfm.2018.533
View details for Web of Science ID 000440175600002
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Time-dependent particle migration and margination in the pressure-driven channel flow of blood
PHYSICAL REVIEW FLUIDS
2018; 3 (3)
View details for DOI 10.1103/PhysRevFluids.3.034302
View details for Web of Science ID 000426786500001
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The steady motion of a closely fitting vesicle in a tube
JOURNAL OF FLUID MECHANICS
2018; 835: 721–61
View details for DOI 10.1017/jfm.2017.743
View details for Web of Science ID 000416945300001
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Einstein viscosity with fluid elasticity
PHYSICAL REVIEW FLUIDS
2018; 3 (1)
View details for DOI 10.1103/PhysRevFluids.3.013301
View details for Web of Science ID 000423134300002
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Effect of Length on the Dynamics of Wall Tethered Polymers in Shear Flow
MACROMOLECULES
2018; 51 (1): 254–65
View details for DOI 10.1021/acs.macromol.7b02032
View details for Web of Science ID 000419999000026
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Suspension flow through an asymmetric T-junction
Journal of Fluid Mechanics
2018; 844
View details for DOI 10.1017/jfm.2018.183
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Growth of viscoelastic wings and the reduction of particle mobility in a viscoelastic shear flow
PHYSICAL REVIEW FLUIDS
2017; 2 (10)
View details for DOI 10.1103/PhysRevFluids.2.103302
View details for Web of Science ID 000413739100002
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Theory to predict particle migration and margination in the pressure-driven channel flow of blood
PHYSICAL REVIEW FLUIDS
2017; 2 (9)
View details for DOI 10.1103/PhysRevFluids.2.093102
View details for Web of Science ID 000410193900001
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Study of the flow unsteadiness in the human airway using large eddy simulation
PHYSICAL REVIEW FLUIDS
2017; 2 (8)
View details for DOI 10.1103/PhysRevFluids.2.083101
View details for Web of Science ID 000407447900001
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Fully resolved viscoelastic particulate simulations using unstructured grids
JOURNAL OF COMPUTATIONAL PHYSICS
2017; 338: 313-338
View details for DOI 10.1016/j.jcp.2017.02.068
View details for Web of Science ID 000400037800015
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Heat/mass transport in shear flow over a reactive surface with inert defects
JOURNAL OF FLUID MECHANICS
2017; 811: 372-399
View details for DOI 10.1017/jfm.2016.762
View details for Web of Science ID 000390352200019
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Numerical simulation of the deterministic vector separation of particles flowing over slanted open cavities
PHYSICAL REVIEW FLUIDS
2016; 1 (8)
View details for DOI 10.1103/PhysRevFluids.1.084101
View details for Web of Science ID 000390345700001
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The Effect of Hematocrit on Platelet Adhesion: Experiments and Simulations.
Biophysical journal
2016; 111 (3): 577-588
Abstract
The volume fraction of red blood cells (RBCs) in a capillary affects the degree to which platelets are promoted to marginate to near a vessel wall and form blood clots. In this work we investigate the relationship between RBC hematocrit and platelet adhesion activity. We perform experiments flowing blood samples through a microfluidic channel coated with type 1 collagen and observe the rate at which platelets adhere to the wall. We compare these results with three-dimensional boundary integral simulations of a suspension of RBCs and platelets in a periodic channel where platelets can adhere to the wall. In both cases, we find that the rate of platelet adhesion varies greatly with the RBC hematocrit. We observe that the relative decrease in platelet activity as hematocrit falls shows a similar profile for simulation and experiment.
View details for DOI 10.1016/j.bpj.2016.06.024
View details for PubMedID 27508441
View details for PubMedCentralID PMC4982930
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Numerical simulations of the rheology of suspensions of rigid spheres at low volume fraction in a viscoelastic fluid under shear
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2016; 234: 51-68
View details for DOI 10.1016/j.jnnfm.2016.04.003
View details for Web of Science ID 000382349900005
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Numerical simulations of the rheology of suspensions of rigid spheres at low volume fraction in a viscoelastic fluid under shear
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2016; 233: 181-197
View details for DOI 10.1016/j.jnnfm.2016.05.004
View details for Web of Science ID 000379560700018
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Experimental observation of the asymmetric instability of intermediate-reduced-volume vesicles in extensional flow
SOFT MATTER
2016; 12 (16): 3787-3796
Abstract
Vesicles provide an attractive model system to understand the deformation of living cells in response to mechanical forces. These simple, enclosed lipid bilayer membranes are suitable for complementary theoretical, numerical, and experimental analysis. A recent study [Narsimhan, Spann, Shaqfeh, J. Fluid Mech., 2014, 750, 144] predicted that intermediate-aspect-ratio vesicles extend asymmetrically in extensional flow. Upon infinitesimal perturbation to the vesicle shape, the vesicle stretches into an asymmetric dumbbell with a cylindrical thread separating the two ends. While the symmetric stretching of high-aspect-ratio vesicles in extensional flow has been observed and characterized [Kantsler, Segre, Steinberg, Phys. Rev. Lett., 2008, 101, 048101] as well as recapitulated in numerical simulations by Narsimhan et al., experimental observation of the asymmetric stretching has not been reported. In this work, we present results from microfluidic cross-slot experiments observing this instability, along with careful characterization of the flow field, vesicle shape, and vesicle bending modulus. The onset of this shape transition depends on two non-dimensional parameters: reduced volume (a measure of vesicle asphericity) and capillary number (ratio of viscous to bending forces). We observed that every intermediate-reduced-volume vesicle that extends forms a dumbbell shape that is indeed asymmetric. For the subset of the intermediate-reduced-volume regime we could capture experimentally, we present an experimental phase diagram for asymmetric vesicle stretching that is consistent with the predictions of Narsimhan et al.
View details for DOI 10.1039/c5sm03004h
View details for Web of Science ID 000374786900014
View details for PubMedID 26984509
View details for PubMedCentralID PMC4838492
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Heat/mass transport in shear flow over a heterogeneous surface with first-order surface-reactive domains
JOURNAL OF FLUID MECHANICS
2015; 782: 260-299
View details for DOI 10.1017/jfm.2015.528
View details for Web of Science ID 000363286400014
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Pearling, wrinkling, and buckling of vesicles in elongational flows
JOURNAL OF FLUID MECHANICS
2015; 777
View details for DOI 10.1017/jfm.2015.345
View details for Web of Science ID 000359643100004
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In Vitro Measurement of Particle Margination in the Microchannel Flow: Effect of Varying Hematocrit
BIOPHYSICAL JOURNAL
2015; 108 (10): 2601-2608
Abstract
It has long been known that platelets undergo margination when flowing in blood vessels, such that there is an excess concentration near the vessel wall. We conduct experiments and three-dimensional boundary integral simulations of platelet-sized spherical particles in a microchannel 30 μm in height to measure the particle-concentration distribution profile and observe its margination at 10%, 20%, and 30% red blood cell hematocrit. The experiments involved adding 2.15-μm-diameter spheres into a solution of red blood cells, plasma, and water and flowing this mixture down a microfluidic channel at a wall shear rate of 1000 s(-1). Fluorescence imaging was used to determine the height and velocity of particles in the channel. Experimental results indicate that margination has largely occurred before particles travel 1 cm downstream and that hematocrit plays a role in the degree of margination. With simulations, we can track the trajectories of the particles with higher resolution. These simulations also confirm that margination from an initially uniform distribution of spheres and red blood cells occurs over the length scale of O(1 cm), with higher hematocrit showing faster margination. The results presented here, from both experiments and 3D simulations, may help explain the relationship between bleeding time in vessel trauma and red blood cell hematocrit as platelets move to a vessel wall.
View details for DOI 10.1016/j.bpj.2015.04.013
View details for Web of Science ID 000354827200020
View details for PubMedID 25992738
View details for PubMedCentralID PMC4457002
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Examining platelet adhesion via Stokes flow simulations and microfluidic experiments.
Soft matter
2015; 11 (2): 355-367
Abstract
While critically important, the platelet function at the high shear rates typical of the microcirculation is relatively poorly understood. Using a large scale Stokes flow simulation, Zhao et al. recently showed that RBC-induced velocity fluctuations cause platelets to marginate into the RBC free near-wall region [Zhao et al., Physics of Fluids, 2012, 24, 011902]. We extend their work by investigating the dynamics of platelets in shear after margination. An overall platelet adhesion model is proposed in terms of a continuous time Markov process and the transition rates are established with numerical simulations involving platelet-wall adhesion. Hydrodynamic drag and Brownian forces are calculated with the boundary element method, while the RBC collisions are incorporated through an autoregressive process. Hookean springs with first order bond kinetics are used to model receptor-ligand bonds formed between the platelet and the wall. The simulations are compared with in vitro microfluidic experiments involving platelet adhesion to Von Willebrand Factor (VWF) coated surfaces.
View details for DOI 10.1039/c4sm01450b
View details for PubMedID 25382632
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Examining platelet adhesion via Stokes flow simulations and microfluidic experiments
SOFT MATTER
2015; 11 (2): 355-367
Abstract
While critically important, the platelet function at the high shear rates typical of the microcirculation is relatively poorly understood. Using a large scale Stokes flow simulation, Zhao et al. recently showed that RBC-induced velocity fluctuations cause platelets to marginate into the RBC free near-wall region [Zhao et al., Physics of Fluids, 2012, 24, 011902]. We extend their work by investigating the dynamics of platelets in shear after margination. An overall platelet adhesion model is proposed in terms of a continuous time Markov process and the transition rates are established with numerical simulations involving platelet-wall adhesion. Hydrodynamic drag and Brownian forces are calculated with the boundary element method, while the RBC collisions are incorporated through an autoregressive process. Hookean springs with first order bond kinetics are used to model receptor-ligand bonds formed between the platelet and the wall. The simulations are compared with in vitro microfluidic experiments involving platelet adhesion to Von Willebrand Factor (VWF) coated surfaces.
View details for DOI 10.1039/c4sm01450b
View details for Web of Science ID 000346060400015
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Nonlinear instability of a supersonic boundary layer with two-dimensional roughness
JOURNAL OF FLUID MECHANICS
2014; 752: 497-520
View details for DOI 10.1017/jfm.2014.266
View details for Web of Science ID 000339273300026
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Scaling analysis and mathematical theory of the interfacial stress rheometer
JOURNAL OF RHEOLOGY
2014; 58 (4): 999-1038
View details for DOI 10.1122/1.4876955
View details for Web of Science ID 000339141600008
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The mechanism of shape instability for a vesicle in extensional flow
JOURNAL OF FLUID MECHANICS
2014; 750: 144-190
View details for DOI 10.1017/jfm.2014.248
View details for Web of Science ID 000337923300011
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Loop subdivision surface boundary integral method simulations of vesicles at low reduced volume ratio in shear and extensional flow
PHYSICS OF FLUIDS
2014; 26 (3)
View details for DOI 10.1063/1.4869307
View details for Web of Science ID 000334179400006
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Singular perturbation theory for predicting extravasation of Brownian particles
JOURNAL OF ENGINEERING MATHEMATICS
2014; 84 (1): 155-171
Abstract
Motivated by recent studies on tumor treatments using the drug delivery of nanoparticles, we provide a singular perturbation theory and perform Brownian dynamics simulations to quantify the extravasation rate of Brownian particles in a shear flow over a circular pore with a lumped mass transfer resistance. The analytic theory we present is an expansion in the limit of a vanishing Péclet number (P), which is the ratio of convective fluxes to diffusive fluxes on the length scale of the pore. We state the concentration of particles near the pore and the extravasation rate (Sherwood number) to O(P1/2). This model improves upon previous studies because the results are valid for all values of the particle mass transfer coefficient across the pore, as modeled by the Damköhler number (κ), which is the ratio of the reaction rate to the diffusive mass transfer rate at the boundary. Previous studies focused on the adsorption-dominated regime (i.e., κ → ∞). Specifically, our work provides a theoretical basis and an interpolation-based approximate method for calculating the Sherwood number (a measure of the extravasation rate) for the case of finite resistance [κ ~ O(1)] at small Péclet numbers, which are physiologically important in the extravasation of nanoparticles. We compare the predictions of our theory and an approximate method to Brownian dynamics simulations with reflection-reaction boundary conditions as modeled by κ. They are found to agree well at small P and for the κ ≪ 1 and κ ≫ 1 asymptotic limits representing the diffusion-dominated and adsorption-dominated regimes, respectively. Although this model neglects the finite size effects of the particles, it provides an important first step toward understanding the physics of extravasation in the tumor vasculature.
View details for DOI 10.1007/s10665-013-9665-2
View details for Web of Science ID 000330955000015
View details for PubMedCentralID PMC3927922
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Singular perturbation theory for predicting extravasation of Brownian particles.
Journal of engineering mathematics
2014; 84 (1): 155-171
Abstract
Motivated by recent studies on tumor treatments using the drug delivery of nanoparticles, we provide a singular perturbation theory and perform Brownian dynamics simulations to quantify the extravasation rate of Brownian particles in a shear flow over a circular pore with a lumped mass transfer resistance. The analytic theory we present is an expansion in the limit of a vanishing Péclet number (P), which is the ratio of convective fluxes to diffusive fluxes on the length scale of the pore. We state the concentration of particles near the pore and the extravasation rate (Sherwood number) to O(P1/2). This model improves upon previous studies because the results are valid for all values of the particle mass transfer coefficient across the pore, as modeled by the Damköhler number (κ), which is the ratio of the reaction rate to the diffusive mass transfer rate at the boundary. Previous studies focused on the adsorption-dominated regime (i.e., κ → ∞). Specifically, our work provides a theoretical basis and an interpolation-based approximate method for calculating the Sherwood number (a measure of the extravasation rate) for the case of finite resistance [κ ~ O(1)] at small Péclet numbers, which are physiologically important in the extravasation of nanoparticles. We compare the predictions of our theory and an approximate method to Brownian dynamics simulations with reflection-reaction boundary conditions as modeled by κ. They are found to agree well at small P and for the κ ≪ 1 and κ ≫ 1 asymptotic limits representing the diffusion-dominated and adsorption-dominated regimes, respectively. Although this model neglects the finite size effects of the particles, it provides an important first step toward understanding the physics of extravasation in the tumor vasculature.
View details for DOI 10.1007/s10665-013-9665-2
View details for PubMedID 24563548
View details for PubMedCentralID PMC3927922
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A method for the direct numerical simulation of hypersonic boundary-layer instability with finite-rate chemistry
JOURNAL OF COMPUTATIONAL PHYSICS
2013; 255: 572-589
View details for DOI 10.1016/j.jcp.2013.07.029
View details for Web of Science ID 000325527100031
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The effect of shear thinning and walls on the sedimentation of a sphere in an elastic fluid under orthogonal shear
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2013; 201: 120-129
View details for DOI 10.1016/j.jnnfm.2013.07.007
View details for Web of Science ID 000326560600011
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Simulations of a sphere sedimenting in a viscoelastic fluid with cross shear flow
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2013; 197: 48-60
View details for DOI 10.1016/j.jnnfm.2013.02.003
View details for Web of Science ID 000319952900007
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The dynamics of a non-dilute vesicle suspension in a simple shear flow
JOURNAL OF FLUID MECHANICS
2013; 725: 709-731
View details for DOI 10.1017/jfm.2013.207
View details for Web of Science ID 000319511200026
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Coarse-grained theory to predict the concentration distribution of red blood cells in wall-bounded Couette flow at zero Reynolds number
PHYSICS OF FLUIDS
2013; 25 (6)
View details for DOI 10.1063/1.4810808
View details for Web of Science ID 000321272600002
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The shape stability of a lipid vesicle in a uniaxial extensional flow
JOURNAL OF FLUID MECHANICS
2013; 719: 345-361
View details for DOI 10.1017/jfm.2013.10
View details for Web of Science ID 000315082000015
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Singular Perturbation Theory for Predicting the Extravasation of Brownian Particles
Journal of Engineering Mathematics
2013
View details for DOI 10.1007/s10665-013-9665-2
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A Conversation with Andreas Acrivos
ANNUAL REVIEW OF CHEMICAL AND BIOMOLECULAR ENGINEERING, VOL 4
2013; 4: 1–21
View details for DOI 10.1146/annurev-chembioeng-061312-103250
View details for Web of Science ID 000321740100002
View details for PubMedID 23394169
- The effect of shear thinning and walls on the sedimentation of a sphere in an elastic fluid under orthogonal shear J. NonNewt. Fluid Mech. 2013; 201: 120 - 129
- A Conversation with Andreas Acrivos Annual Reviews of Chemical and Biomolecular Engineering 2013; 1 (16): 1-21
- Coarse-grained theory to predict the concentration distribution of red blood cells in wall-bound Couette flow at zero Reynolds number Phys. Fluids 2013; 25: 061901
- The rheology of a non-dilute vesicle suspension in a simple shear flow J. Fluid Mech. 2013; 725: 709 - 731
- A method for the direct numerical simulation of hypersonic boundary-layer instability with finite-rate chemistry J. Comp. Phys. 2013; 255: 572-589
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Flow of power-law fluids in fixed beds of cylinders or spheres
JOURNAL OF FLUID MECHANICS
2012; 713: 491-527
View details for DOI 10.1017/jfm.2012.471
View details for Web of Science ID 000311889500022
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Buckling transitions of an elastic filament in a viscous stagnation point flow
PHYSICS OF FLUIDS
2012; 24 (12)
View details for DOI 10.1063/1.4771606
View details for Web of Science ID 000312833500022
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Effects of viscoelasticity in the high Reynolds number cylinder wake
JOURNAL OF FLUID MECHANICS
2012; 693: 297-318
View details for DOI 10.1017/jfm.2011.531
View details for Web of Science ID 000300022300012
- The effects of viscoelasticity in the high Reynolds number cylinder wake J. Fluid Mech. 2012; 693: 297-318
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Shear-induced particle migration and margination in a cellular suspension
PHYSICS OF FLUIDS
2012; 24 (1)
View details for DOI 10.1063/1.3677935
View details for Web of Science ID 000300527000008
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The dynamics of a vesicle in a wall-bound shear flow
PHYSICS OF FLUIDS
2011; 23 (12)
View details for DOI 10.1063/1.3669440
View details for Web of Science ID 000298642400003
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Numerical Simulation of Polymer Injection in Turbulent Flow Past a Circular Cylinder
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
2011; 133 (10)
View details for DOI 10.1115/1.4004960
View details for Web of Science ID 000295623700014
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A high-order numerical method to study hypersonic boundary-layer instability including high-temperature gas effects
PHYSICS OF FLUIDS
2011; 23 (8)
View details for DOI 10.1063/1.3614526
View details for Web of Science ID 000294483500027
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A computational study of the influence of viscoelasticity on the interfacial dynamics of dip coating flow
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2011; 166 (12-13): 614-627
View details for DOI 10.1016/j.jnnfm.2011.03.002
View details for Web of Science ID 000292363700002
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Shear-induced platelet margination in a microchannel
PHYSICAL REVIEW E
2011; 83 (6)
Abstract
The lateral migration of platelets in a microchannel is studied numerically where the hydrodynamic interactions between red cells, platelets, and vessel walls are resolved by the Stokes flow boundary integral equations. The simulations provide a clear physical description of the expulsion of the platelets by the velocity fluctuations in the core cellular flow toward the cell-depleted layer near the wall. The lateral migration is shown to be diffusional, and we further demonstrate, in agreement with previous experiments, that the diffusivity scales sublinearly with the shear rate if the relevant capillary number, Ca<1, as a result of its intrinsic dependence on the deformation of red cells.
View details for DOI 10.1103/PhysRevE.83.061924
View details for Web of Science ID 000292263600010
View details for PubMedID 21797420
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Floquet stability analysis of viscoelastic flow over a cylinder
16th International Workshop on Numerical Methods for Non-Newtonian Flows
ELSEVIER SCIENCE BV. 2011: 554–65
View details for DOI 10.1016/j.jnnfm.2011.02.005
View details for Web of Science ID 000291286700004
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Slip-link simulations of entangled polymers in planar extensional flow: Disentanglement modified extensional thinning
JOURNAL OF RHEOLOGY
2011; 55 (3): 463-483
View details for DOI 10.1122/1.3549296
View details for Web of Science ID 000289733400001
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The dynamics of a vesicle in simple shear flow
JOURNAL OF FLUID MECHANICS
2011; 674: 578-604
View details for DOI 10.1017/S0022112011000115
View details for Web of Science ID 000290112900022
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The Shear Flow Processing of Controlled DNA Tethering and Stretching for Organic Molecular Electronics
ACS NANO
2011; 5 (1): 275-282
Abstract
DNA has been recently explored as a powerful tool for developing molecular scaffolds for making reproducible and reliable metal contacts to single organic semiconducting molecules. A critical step in the process of exploiting DNA-organic molecule-DNA (DOD) array structures is the controlled tethering and stretching of DNA molecules. Here we report the development of reproducible surface chemistry for tethering DNA molecules at tunable density and demonstrate shear flow processing as a rationally controlled approach for stretching/aligning DNA molecules of various lengths. Through enzymatic cleavage of λ-phage DNA to yield a series of DNA chains of various lengths from 17.3 μm down to 4.2 μm, we have investigated the flow/extension behavior of these tethered DNA molecules under different flow strengths in the flow-gradient plane. We compared Brownian dynamic simulations for the flow dynamics of tethered λ-DNA in shear, and found our flow-gradient plane experimental results matched well with our bead-spring simulations. The shear flow processing demonstrated in our studies represents a controllable approach for tethering and stretching DNA molecules of various lengths. Together with further metallization of DNA chains within DOD structures, this bottom-up approach can potentially enable efficient and reliable fabrication of large-scale nanoelectronic devices based on single organic molecules, therefore opening opportunities in both fundamental understanding of charge transport at the single molecular level and many exciting applications for ever-shrinking molecular circuits.
View details for DOI 10.1021/nn102669b
View details for PubMedID 21126082
- Conformational hysteresis of flexible polymers in 3-D, incompressible, linear flows J. Chem. Phys. 2011
- Buckling transitions of a beam at a stagnation point 2011
- Numerical simulations of hypersonic boundary-layer instability with localized roughness 2011
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Effect of Solvent Quality on the Coil-Stretch Transition
MACROMOLECULES
2010; 43 (24): 10679-10691
View details for DOI 10.1021/ma1019945
View details for Web of Science ID 000285429400068
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Lateral drift and concentration instability in a suspension of bubbles induced by Marangoni stresses at zero Reynolds number
PHYSICS OF FLUIDS
2010; 22 (10)
View details for DOI 10.1063/1.3491499
View details for Web of Science ID 000283748900002
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Simulations of three-dimensional viscoelastic flows past a circular cylinder at moderate Reynolds numbers
JOURNAL OF FLUID MECHANICS
2010; 651: 415-442
View details for DOI 10.1017/S0022112009994083
View details for Web of Science ID 000278212600017
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Disturbance evolution in a Mach 4.8 boundary layer with two-dimensional roughness-induced separation and shock
JOURNAL OF FLUID MECHANICS
2010; 648: 435-469
View details for DOI 10.1017/S0022112009992758
View details for Web of Science ID 000277255000018
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Reynolds-averaged modeling of polymer drag reduction in turbulent flows
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2010; 165 (7-8): 376-384
View details for DOI 10.1016/j.jnnfm.2010.01.013
View details for Web of Science ID 000276285000006
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Flow controlled coil-to-stretch transition of a single DNA molecule: A brownian dynamics study
AMER CHEMICAL SOC. 2010
View details for Web of Science ID 000208189302069
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Linear and non-linear disturbance evolution in a compressible boundary-layer with localized roughness
7th IUTAM Symposium on Laminar-Turbulent Transition
SPRINGER. 2010: 271–276
View details for DOI 10.1007/978-90-481-3723-7_43
View details for Web of Science ID 000277097200043
- A numerical method to simulate hypersonic boundary layers with finite-rate chemistry 2010
- Numerical simulations of hypersonic boundary-layer instability with wall blowing 2010
- Hypersonic boundary-layer instability with chemical reactions 2010
- Numerical simulation of the margination of platelets in the microvasculature 2010
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The conformational dynamics of lambda-DNA in the anti-Brownian electrokinetic trap: Brownian dynamics and Monte Carlo simulation
JOURNAL OF CHEMICAL PHYSICS
2009; 131 (22)
Abstract
In this work, we examine the conformational dynamics of long polymer molecules under confinement, as in the recently developed anti-Brownian electrokinetic (ABEL) trap [A. Cohen and W. Moerner, Proc. Natl. Acad. Sci. USA. 103, 4362 (2006)]. We analyze polymer motion using Brownian dynamics simulations (bead-spring and bead-rod models) and via Monte Carlo methods. We first verify Cohen and Moerner's (2007) single molecule observations regarding the existence of short time correlations [Phys. Rev. Lett. 98, 116001 (2007)] in the motion of a polymer's center of mass, which arise due to fluctuating hydrodynamic interactions. Thereafter, following Cohen and Moerner, we use principal component analysis to extract the principal modes governing polymer conformation and find that confinement and backbone bending only affect small polymers and should not play a significant role in the dynamics of long polymers such as lambda-DNA. We find excellent agreement between our principal component analysis modes and those measured by Cohen and Moerner [Proc. Natl. Acad. Sci. U.S.A. 104, 12622 (2007)]. Finally, to explore the effect of excluded volume, in particular, the effect of the excluded volume parameter (z), we use image-image correlations to examine its relation to polymer dynamics. Image-image correlation measurements performed on lambda-DNA in the ABEL trap did not display a simple exponential-type behavior and motivated the use of stretched exponential functions to determine the characteristic timescale (tau) governing conformational dynamics. We show that tau scales with polymer length as N(2) and decreases with increasing z. Furthermore, we can collapse a variety of data when tauN(-2) is plotted with respect to N/z(m) (m=0.14 for freespace and 0.366 for walls).
View details for DOI 10.1063/1.3251058
View details for Web of Science ID 000272803000070
View details for PubMedID 20001082
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Experimental and Numerical Studies of Tethered DNA Shear Dynamics in the Flow-Gradient Plane
MACROMOLECULES
2009; 42 (22): 9170-9182
View details for DOI 10.1021/ma901348j
View details for Web of Science ID 000271756500080
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Slip-Link Simulations of Entangled, Finitely Extensible, Wormlike Chains in Shear Flow
MACROMOLECULES
2009; 42 (18): 7168-7183
View details for DOI 10.1021/ma802555r
View details for Web of Science ID 000269699400045
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The effect of Brownian motion on the stability of sedimenting suspensions of polarizable rods in an electric field
JOURNAL OF FLUID MECHANICS
2009; 624: 361-388
View details for DOI 10.1017/S0022112008005405
View details for Web of Science ID 000265754000018
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Hydrodynamic interactions in metal rodlike-particle suspensions due to induced charge electroosmosis
PHYSICAL REVIEW E
2009; 79 (1)
Abstract
We present a theoretical and experimental study of the role of hydrodynamic interactions on the motion and dispersion of metal rodlike particles in the presence of an externally applied electric field. In these systems, the electric field polarizes the particles and induces an electroosmotic flow relative to the surface of each particle. The simulations include the effect of the gravitational body force, buoyancy, far-field hydrodynamic interactions, and near-field lubrication forces. The particles in the simulations and experiments were observed to experience repeated pairing interactions in which they come together axially with their ends approaching each other, slide past one another until their centers approach, and then push apart. These interactions were confirmed in measurements of particle orientations and velocities, pair distribution functions, and net dispersion of the suspension. For large electric fields, the pair distribution functions show accumulation and depletion regions consistent with many pairing events. For particle concentrations of 10;{8}particles/mL and higher, dispersion within the suspension dramatically increases with increased field strength.
View details for DOI 10.1103/PhysRevE.79.011402
View details for Web of Science ID 000262976600043
View details for PubMedID 19257030
- Micro- and Nanouidic Simulations for BWA Sensing and Blood Additive Development 2009
- The Dynamics of Vesicles in Shear Flow 2009
- Uncertainty quantification for linear and weakly non-linear supersonic boundary-layer instability 2009
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Brownian demixing and wall effects in sedimenting suspensions of orientable particles
PHYSICAL REVIEW E
2008; 78 (5)
Abstract
We describe the Brownian demixing of sedimenting suspensions, a recently discovered phenomenon in which increases in the thermal energy can destabilize a system of orientable particles subjected to a torque to fluctuations in concentration. Through use of Brownian dynamics simulation and a mean-field analysis, we demonstrate that demixing occurs in a model system composed of slender rigid rods sedimenting between no-slip walls. Additionally, we describe the effects of wall separation distance on suspension stability.
View details for DOI 10.1103/PhysRevE.78.055301
View details for Web of Science ID 000261213800005
View details for PubMedID 19113180
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International workshop on mesoscale and multiscale description of complex fluids (IWMMCOF'06), Prato, Italy, July 5-8, 2006
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2008; 149 (1-3): 1-2
View details for DOI 10.1016/j.jnnfm.2007.07.006
View details for Web of Science ID 000253553400001
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Tethered DNA shear dynamics in the flow gradient plane: application to double tethering
Korea-Australia Rheology Conference
KOREAN SOC RHEOLOGY. 2007: 141–46
View details for Web of Science ID 000251728100006
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The dynamics of the coil-stretch transition for long, flexible polymers in planar mixed flows
JOURNAL OF RHEOLOGY
2007; 51 (5): 947-969
View details for DOI 10.1122/1.2754293
View details for Web of Science ID 000249386300010
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Dynamics of DNA polymers in post arrays: Comparison of single molecule experiments and simulations
MACROMOLECULES
2007; 40 (10): 3848-3859
View details for DOI 10.1021/ma062892e
View details for Web of Science ID 000246280600049
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Ergodicity-breaking and the unraveling dynamics of a polymer in linear and nonlinear extensional flows
JOURNAL OF RHEOLOGY
2007; 51 (3): 561-574
View details for DOI 10.1122/1.2714820
View details for Web of Science ID 000246502300013
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The individualistic dynamics of entangled DNA in solution
MACROMOLECULES
2007; 40 (7): 2461-2476
View details for DOI 10.1021/ma062932e
View details for Web of Science ID 000245208400024
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Dynamics of DNA tumbling in shear to rotational mixed flows: Pathways and periods
PHYSICAL REVIEW E
2007; 75 (4)
Abstract
The tumbling dynamics of DNA have been examined via experiments and Brownian dynamics (BD) simulations in mixed flows that vary from pure shear to pure rotation. In shear, tumbling pathways and periods agree well with earlier studies; in rotation-dominated flows, a new tumbling pathway is identified and experimentally observed. Based on these results, we have developed robust scaling laws for DNA tumbling in both shear and rotational flows and have found a critical flow-type parameter for transition from the shearlike flow regime to the rotation-dominated one.
View details for DOI 10.1103/PhysRevE.75.040802
View details for Web of Science ID 000246073900013
View details for PubMedID 17500855
- Numerical simulations of hypersonic boundary-layer instability using different gas models 2007
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Report of the symposium on interactions for dispersed systems in Newtonian and viscoelastic fluids, Guanajuato, Mexico, 2006
PHYSICS OF FLUIDS
2006; 18 (12)
View details for DOI 10.1063/1.2396902
View details for Web of Science ID 000243158200001
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The effect of stratification on the wave number selection in the instability of sedimenting spheroids
PHYSICS OF FLUIDS
2006; 18 (12)
View details for DOI 10.1063/1.2396913
View details for Web of Science ID 000243158200003
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Stabilization of a suspension of sedimenting rods by induced-charge electrophoresis
PHYSICS OF FLUIDS
2006; 18 (12)
View details for DOI 10.1063/1.2404948
View details for Web of Science ID 000243158200013
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Direct numerical simulation of polymer-induced drag reduction in turbulent boundary layer flow of inhomogeneous polymer solutions
JOURNAL OF FLUID MECHANICS
2006; 566: 153-162
View details for DOI 10.1017/S0022112006002321
View details for Web of Science ID 000241996800006
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Hydrodynamic interactions in the induced-charge electrophoresis of colloidal rod dispersions
JOURNAL OF FLUID MECHANICS
2006; 563: 223-259
View details for DOI 10.1017/S0022112006001376
View details for Web of Science ID 000241085500011
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Effect of flexibility on the shear-induced migration of short-chain polymers in parabolic channel flow
JOURNAL OF FLUID MECHANICS
2006; 557: 297-306
View details for DOI 10.1017/S0022112006000243
View details for Web of Science ID 000238820700013
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The growth of concentration fluctuations in dilute dispersions of orientable and deformable particles under sedimentation
JOURNAL OF FLUID MECHANICS
2006; 553: 347-388
View details for DOI 10.1017/S0022112006009025
View details for Web of Science ID 000237366800015
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Ergodicity breaking and conformational hysteresis in the dynamics of a polymer tethered at a surface stagnation point
JOURNAL OF CHEMICAL PHYSICS
2006; 124 (9)
Abstract
We study the dynamics of long chain polymer molecules tethered to a plane wall and subjected to a stagnation point flow. Using a combination of theory and numerical techniques, including Brownian dynamics (BD), we demonstrate that a chain conformation hysteresis exists even for freely draining (FD) chains. Hydrodynamic interactions (HI) between the polymer and the wall are included in the BD simulations. We find qualitative agreement between the FD and HI simulations, with both exhibiting simultaneous coiled and stretched states for a wide range of fixed flow strengths. The range of state coexistence is understood by considering an equivalent projected equilibrium problem of a two state reaction. Using this formalism, we construct Kramers rate theory (from the inverse mean first passage time for a Markov process) for the hopping transition from coil to stretch and stretch to coil. The activation energy for this rate is found to scale proportionally to chain length or Kuhn step number. Thus, in the limit of infinite chain size the hopping rates at a fixed value of the suitably defined Deborah number approach zero and the states are "frozen." We present the results that demonstrate this "ergodicity breaking."
View details for DOI 10.1063/1.2171963
View details for Web of Science ID 000235828300035
View details for PubMedID 16526871
- Report on 'the Symposium `Interactions for Dispersed Systems in Newtonian and Viscoelastic Fluids 2006
- Conference Report on the International Workshop on Mesoscale and Multiscale Description of Complex Fluids - IWMMCOF '06 2006
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The dynamics of single-molecule DNA in flow
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2005; 130 (1): 1-28
View details for DOI 10.1016/j.jnnfm.2005.05.011
View details for Web of Science ID 000232728900001
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The influence of polymer concentration and chain architecture on free surface displacement flows of polymeric fluids
JOURNAL OF RHEOLOGY
2005; 49 (5): 929-962
View details for DOI 10.1122/1.2000969
View details for Web of Science ID 000231777600001
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An experimental and numerical investigation of drag reduction in a turbulent boundary layer using a rigid rodlike polymer
PHYSICS OF FLUIDS
2005; 17 (8)
View details for DOI 10.1063/1.1993307
View details for Web of Science ID 000231392000026
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Characteristic periodic motion of polymers in shear flow
PHYSICAL REVIEW LETTERS
2005; 95 (1)
Abstract
The motion of both free and tethered polymer molecules as well as rigid Brownian rods in unbound shear flow is found to be characterized by a clear periodicity or tumbling frequency. Periodicity is shown using a combination of single molecule DNA experiments and computer simulations. In all cases, we develop scaling laws for this behavior and demonstrate that the frequency of characteristic periodic motion scales sublinearly with flow rate.
View details for DOI 10.1103/PhysRevLett.95.018301
View details for Web of Science ID 000230275500075
View details for PubMedID 16090661
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New answers on the interaction between polymers and vortices in turbulent flows
FLOW TURBULENCE AND COMBUSTION
2005; 74 (4): 311-329
View details for DOI 10.1004/s10494-005-9002-6
View details for Web of Science ID 000235281500002
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The dynamic mechanism for turbulent drag reduction using rigid fibers based on Lagrangian conditional statistics
PHYSICS OF FLUIDS
2005; 17 (6)
View details for DOI 10.1063/1.1925447
View details for Web of Science ID 000229749500011
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Viscoelastic effects on interfacial dynamics in air-liquid displacement under gravity stabilization
JOURNAL OF FLUID MECHANICS
2005; 531: 59-83
View details for DOI 10.1017/S0022112005004131
View details for Web of Science ID 000230051000004
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Dynamics of DNA in the flow-gradient plane of steady shear flow: Observations and simulations
MACROMOLECULES
2005; 38 (5): 1967-1978
View details for DOI 10.1021/ma0480796
View details for Web of Science ID 000227448200059
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A smooth particle-mesh Ewald algorithm for Stokes suspension simulations: The sedimentation of fibers
PHYSICS OF FLUIDS
2005; 17 (3)
View details for DOI 10.1063/1.1862262
View details for Web of Science ID 000227372600031
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Shear thinning and tumbling dynamics of single polymers in the flow-gradient plane
MACROMOLECULES
2005; 38 (2): 581-592
View details for DOI 10.1021/ma0480771
View details for Web of Science ID 000226466700047
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Direct numerical simulation of polymer-induced drag reduction in turbulent boundary layer flow
PHYSICS OF FLUIDS
2005; 17 (1)
View details for DOI 10.1063/1.1829751
View details for Web of Science ID 000226358000005
- Viscoelastic turbulent boundary layer with near wall injection of polymer molecules 2005
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Induced-charge electrophoresis in suspensions of rodlike particles: Theory and simulations
ASME International Mechanical Engineering Congress and Exposition
AMER SOC MECHANICAL ENGINEERS. 2005: 251–256
View details for Web of Science ID 000243038600033
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Microstructure in the sedimentation of anisotropic and deformable particles
ASME International Mechanical Engineering Congress and Exposition
AMER SOC MECHANICAL ENGINEERS. 2005: 797–803
View details for Web of Science ID 000243038600101
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Brownian dynamics simulations of a flexible polymer chain which includes continuous resistance and multibody hydrodynamic interactions
JOURNAL OF CHEMICAL PHYSICS
2005; 122 (1)
Abstract
Using methods adapted from the simulation of suspension dynamics, we have developed a Brownian dynamics algorithm with multibody hydrodynamic interactions for simulating the dynamics of polymer molecules. The polymer molecule is modeled as a chain composed of a series of inextensible, rigid rods with constraints at each joint to ensure continuity of the chain. The linear and rotational velocities of each segment of the polymer chain are described by the slender-body theory of Batchelor [J. Fluid Mech. 44, 419 (1970)]. To include hydrodynamic interactions between the segments of the chain, the line distribution of forces on each segment is approximated by making a Legendre polynomial expansion of the disturbance velocity on the segment, where the first two terms of the expansion are retained in the calculation. Thus, the resulting linear force distribution is specified by a center of mass force, couple, and stresslet on each segment. This method for calculating the hydrodynamic interactions has been successfully used to simulate the dynamics of noncolloidal suspensions of rigid fibers [O. G. Harlen, R. R. Sundararajakumar, and D. L. Koch, J. Fluid Mech. 388, 355 (1999); J. E. Butler and E. S. G. Shaqfeh, J. Fluid Mech. 468, 204 (2002)]. The longest relaxation time and center of mass diffusivity are among the quantities calculated with the simulation technique. Comparisons are made for different levels of approximation of the hydrodynamic interactions, including multibody interactions, two-body interactions, and the "freely draining" case with no interactions. For the short polymer chains studied in this paper, the results indicate a difference in the apparent scaling of diffusivity with polymer length for the multibody versus two-body level of approximation for the hydrodynamic interactions.
View details for DOI 10.1063/1.1828432
View details for Web of Science ID 000226698500061
View details for PubMedID 15638694
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Effect of hydrodynamic interactions on DNA dynamics in extensional flow: Simulation and single molecule experiment
MACROMOLECULES
2004; 37 (24): 9242-9256
View details for DOI 10.1021/ma049461l
View details for Web of Science ID 000225371200055
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Numerical simulation of turbulent drag reduction using rigid fibres
JOURNAL OF FLUID MECHANICS
2004; 518: 281-317
View details for DOI 10.1017/S0022112004001144
View details for Web of Science ID 000225335600012
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Influence of viscoelasticity on the interfacial dynamics of air displacing fluid flows - a computational study
13th International Workshop on Numerical Methods for Non-Newtonian Flows
ELSEVIER SCIENCE BV. 2004: 313–32
View details for DOI 10.1016/j.jnnfm.2004.06.010
View details for Web of Science ID 000225311700023
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On the coherent drag-reducing and turbulence-enhancing behaviour of polymers in wall flows
JOURNAL OF FLUID MECHANICS
2004; 514: 271-280
View details for DOI 10.1017/S0022112004000291
View details for Web of Science ID 000224223600011
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Simulated polymer stretch in a turbulent flow using Brownian dynamics
JOURNAL OF FLUID MECHANICS
2004; 504: 61-71
View details for DOI 10.1017/S0022112004008250
View details for Web of Science ID 000221274000003
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Effect of confinement on dynamics and rheology of dilute DNA solutions. I. Entropic spring force under confinement and a numerical algorithm
JOURNAL OF RHEOLOGY
2004; 48 (2): 281-298
View details for DOI 10.1122/1.1648642
View details for Web of Science ID 000220073600002
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The effect of confinement on dynamics and rheology of dilute deoxyribose nucleic acid solutions. II. Effective rheology and single chain dynamics
JOURNAL OF RHEOLOGY
2004; 48 (2): 299-318
View details for DOI 10.1122/1.1648643
View details for Web of Science ID 000220073600003
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On the polymer entropic force singularity and its relation to extensional stress relaxation and filament recoil
JOURNAL OF RHEOLOGY
2004; 48 (1): 209-221
View details for DOI 10.1122/1.1626679
View details for Web of Science ID 000187952400013
- A computational study of the interfacial dynamics of free surface viscoelastic fluid flows 2004
- The Effect of Hydrodynamic Interactions on the Dynamics of DNA in Extensional Flow: Simulation and Single Molecule Experiment Macromolecules 2004; 37: 9242-9256
- Non-equilibrium behavior of DNA molecules in flows of dilute and concentrated solutions 2004
- Solution rheology and it role in the mechanisms of turbulent drag reduction 2004
- Effect of confinement on the dynamics and rheology of dilute DNA solutions. II. Effective rheology and single chain dynamics J. Journal of Rheology 2004; 2 (48): 299-318
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Observation of polymer conformation hysteresis in extensional flow
SCIENCE
2003; 301 (5639): 1515-1519
Abstract
Highly extensible Escherichia coli DNA molecules in planar extensional flow were visualized in dilute solution by fluorescence microscopy. For a narrow range of flow strengths, the molecules were found in either a coiled or highly extended conformation, depending on the deformation history of the polymer. This conformation hysteresis persists for many polymer relaxation times and is due to conformation-dependent hydrodynamic forces. Polymer conformational free-energy landscapes were calculated from computer simulations and show two free-energy minima for flow strengths near the coil-stretch transition. Hysteresis cycles may directly influence bulk-solution stresses and the development of stress-strain relations for dilute polymer flows.
View details for Web of Science ID 000185255300044
View details for PubMedID 12970560
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The configurational phase transitions of flexible polymers in planar mixed flows near simple shear
JOURNAL OF CHEMICAL PHYSICS
2003; 119 (5): 2908-2914
View details for DOI 10.1063/1.1587698
View details for Web of Science ID 000184242100048
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Visualization of molecular fluctuations near the critical point of the coil-stretch transition in polymer elongation
MACROMOLECULES
2003; 36 (12): 4544-4548
View details for DOI 10.1021/ma034073p
View details for Web of Science ID 000183526900041
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Drop breakup in the flow through fixed fiber beds: An experimental and computational investigation
PHYSICS OF FLUIDS
2003; 15 (5): 1146-1157
View details for DOI 10.1063/1.1557051
View details for Web of Science ID 000182104400008
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A computational study of DNA separations in sparse disordered and periodic arrays of posts
JOURNAL OF CHEMICAL PHYSICS
2003; 118 (6): 2941-2951
View details for DOI 10.1063/1.1532729
View details for Web of Science ID 000180564800054
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Shear forces between tethered polymer chains as a function of compression, sliding velocity, and solvent quality
MACROMOLECULES
2003; 36 (2): 389-398
View details for DOI 10.1021/ma011207v
View details for Web of Science ID 000180601500021
- Numerical Simulation of the High Drag Reduction Regime in Polymer Solutions 2003
- Brownian dynamics simulation in a turbulent channel flow 2003
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Summary of the XIIth International Workshop on Numerical Methods for Non-Newtonian Flows, Seascape Resort, Monterey Bay, CA, USA, 15-17 July 2001
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2002; 108 (1-3): V-V
View details for Web of Science ID 000180381900001
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Brownian dynamics simulations of bead-rod and bead-spring chains: numerical algorithms and coarse-graining issues
12th International Workshop on Numerical Methods for Non-Newtonian Flows
ELSEVIER SCIENCE BV. 2002: 227–55
View details for Web of Science ID 000180381900012
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Dynamic simulations of the inhomogeneous sedimentation of rigid fibres
JOURNAL OF FLUID MECHANICS
2002; 468: 205-237
View details for DOI 10.1017/S0022112002001544
View details for Web of Science ID 000178731400008
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Dynamics and configurational fluctuations of single DNA molecules in linear mixed flows
PHYSICAL REVIEW E
2002; 66 (1)
Abstract
We examine the dynamics of DNA molecules in mixed flows where the ratio of vorticity to strain rate may be slightly above or below unity via Brownian dynamics simulation. We find that the chain dynamics in these flows are dramatically different than those found for simple shear flow. When the strain rate exceeds vorticity, the dynamics are found to be driven by the extra amount of straining. For vorticity-dominated flows, a periodicity in chain extension is observed with considerable chain deformation.
View details for DOI 10.1103/PhysRevE.66.011915
View details for Web of Science ID 000177200500061
View details for PubMedID 12241392
- A study of viscoelastic free surface flows by the finite element method: Hele-Shaw and slot coating flows J. NonNewtonian Fluid Mech. 2002; 108: 327-362
- Brownian Dynamics Simulations of Bead-Rod and Bead-Spring Chains: Numerical Algorithms and Coarse Graining Issues J. NonNewtonian Fluid Mech. 2002; 108: 227-255
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Electrophoresis of DNA adsorbed to a cationic supported bilayer
LANGMUIR
2001; 17 (23): 7396-7401
View details for Web of Science ID 000172123700036
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An experimental and simulation study of dilute polymer solutions in exponential shear flow: Comparison to uniaxial and planar extensional flows
JOURNAL OF RHEOLOGY
2001; 45 (2): 321-349
View details for Web of Science ID 000167378100002
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Dynamics of dilute and semidilute DNA solutions in the start-up of shear flow
JOURNAL OF RHEOLOGY
2001; 45 (2): 421-450
View details for Web of Science ID 000167378100007
- The dynamics of dilute and semidilute DNA solutions in the startup of shear flow Journal of Rheology 2001; 45: 421-450
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Observations of elastic instabilities in lid-driven cavity flow
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2000; 94 (1): 15-35
View details for Web of Science ID 000089303200002
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Dynamic simulation of freely-draining, flexible bead-rod chains: Start-up of extensional and shear flow (vol 76, pg 43, 1998)
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
2000; 92 (2-3): 275-278
View details for Web of Science ID 000088810500010
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Relating the microscopic and macroscopic response of a polymeric fluid in a shearing flow
PHYSICAL REVIEW LETTERS
2000; 85 (9): 2018-2021
Abstract
The microscopic and macroscopic response of a polymer solution in start-up shear flow was investigated using fluorescence microscopy of single molecules, bulk viscosity measurements, and Brownian dynamics simulations. An overshoot in viscosity was observed upon flow inception and understood via the observed molecular extension and by simulation findings. Increasing the polymer concentration up to six times the overlap concentration ( C(*)) has no effect on the character of the dynamics of individual molecules.
View details for Web of Science ID 000088965300060
View details for PubMedID 10970672
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Brownian dynamics simulations of single DNA molecules in shear flow
JOURNAL OF RHEOLOGY
2000; 44 (4): 713-742
View details for Web of Science ID 000088080100003
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Ion-assisted etching and profile development of silicon in molecular and atomic chlorine
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
2000; 18 (1): 172-190
View details for Web of Science ID 000085375600033
- The Ion-assisted Etching and Profile Development of Silicon in Molecular and Atomic Chlorine J. Vac. Sci. Technol. 2000; 1 (B18): 172-190
- An experimental/theoretical study of elastic instabilities in free surface displacement flows 2000
- Brownian dynamics simulations of DNA chains with hydrodynamic interaction 2000
- Observations of the Viscoelastic Instabilities in Lid Driven Cavity Flow J. NonNewtonian Fluid Mech. 2000; 94: 15
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Modeling of viscoelastic lid driven cavity flow using finite element simulations
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1999; 88 (1-2): 99-131
View details for Web of Science ID 000083718500005
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Observations of ribbing instabilities in elastic fluid flows with gravity stabilization
JOURNAL OF FLUID MECHANICS
1999; 399: 49-83
View details for Web of Science ID 000083977400002
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Report on the IUTAM symposium on viscoelastic fluid mechanics: effects of molecular modeling
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1999; 82 (2-3): 127-134
View details for Web of Science ID 000079202100001
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Brownian dynamics simulations of the stress and molecular configuration of polymers in exponential and linearly-ramped shear flow
IUTAM Symposium on Viscoelastic Fluid Mechanics - Effects of Molecular Modelling
ELSEVIER SCIENCE BV. 1999: 139–65
View details for Web of Science ID 000079202100002
- The modelling of viscoelastic lid-driven cavity flows using finite element simulations J. NonNewtonian Fluid Mech. 1999; 88: 99-131
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A numerical study of the sedimentation of fibre suspensions
JOURNAL OF FLUID MECHANICS
1998; 376: 149-182
View details for Web of Science ID 000077705600008
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Flow of a viscoelastic fluid between eccentric cylinders: impact on flow stability
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1998; 80 (1): 59-87
View details for Web of Science ID 000076917300002
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Experimental and theoretical observations of elastic instabilities in eccentric cylinder flows: local versus global instability
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1998; 80 (1): 1-58
View details for Web of Science ID 000076917300001
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Rheology of polymer brushes: A Brownian dynamics study
MACROMOLECULES
1998; 31 (16): 5474-5486
View details for Web of Science ID 000075347600035
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Growth of SiC films via C-60 precursors and a model for the profile development of the silicon underlayer
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
1998; 16 (4): 2385-2394
View details for Web of Science ID 000074852700059
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Relaxation of dilute polymer solutions following extensional flow
International Conference on the Dynamics of Polymeric Liquids
ELSEVIER SCIENCE BV. 1998: 79–110
View details for Web of Science ID 000073289800006
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Dynamic simulation of freely-draining, flexible bead-rod chains: Start-up of extensional and shear flow
International Conference on the Dynamics of Polymeric Liquids
ELSEVIER SCIENCE BV. 1998: 43–78
View details for Web of Science ID 000073289800005
- The growth of SiC lms via C60 precursors and a model for the profile development of the silicon underlayer JVST A 1998; 4 (16): 2385-2394
- Drop Breakup in Fixed Bed Flows as Model Stochastic Flow Fields 1998
- Fingering in the Fluid-Fluid Displacement of Highly Elastic Fluids 1998
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Drop breakup in the flow through fixed beds via stochastic simulation in model Gaussian fields
PHYSICS OF FLUIDS
1997; 9 (11): 3209-3226
View details for Web of Science ID A1997YE01200012
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Ion-assisted etching and profile development of silicon in molecular chlorine
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
1997; 15 (4): 1902-1912
View details for Web of Science ID A1997XL33500015
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The conformation change of model polymers in stochastic flow fields: Flow through fixed beds
PHYSICS OF FLUIDS
1997; 9 (5): 1222-1234
View details for Web of Science ID A1997WW80100005
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Brownian dynamics simulations of sheared ''wet'' polymer brushes
AMER CHEMICAL SOC. 1997: 480-POLY
View details for Web of Science ID A1997WP18703217
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Dynamic simulation of freely draining flexible polymers in steady linear flows
JOURNAL OF FLUID MECHANICS
1997; 334: 251-291
View details for Web of Science ID A1997WR67900010
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Oscillatory shear of a confined fiber suspension
JOURNAL OF RHEOLOGY
1997; 41 (2): 445-466
View details for Web of Science ID A1997WL62600016
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Rheology of ''wet'' polymer brushes via Brownian dynamics simulation: Steady vs oscillatory shear
PHYSICAL REVIEW LETTERS
1997; 78 (6): 1182-1185
View details for Web of Science ID A1997WG88800050
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Cross-streamline migration of slender Brownian fibres in plane poiseuille flow
JOURNAL OF FLUID MECHANICS
1997; 332: 23-39
View details for Web of Science ID A1997WL97800002
- Drop breakup in flow through fixed beds Phys. Fluids 1997; 11 (9): 3209-3226
- The Ion-assisted Etching and Profile Development of Silicon in Chlorine J. Vac. Sci. Technol. 1997; 4 (A 15): 1902-1912
- The rheology of `wet' polymer brushes via Brownian dynamics simulation: steady vs. oscillatory shear Phys. Rev. Lett. 1997; 6 (78): 1182-1185
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A numerical study of the rheological properties of suspensions of rigid, non-Brownian fibres
JOURNAL OF FLUID MECHANICS
1996; 329: 155-186
View details for Web of Science ID A1996WA84000009
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Experimental investigation of the sedimentation of a dilute fiber suspension
PHYSICAL REVIEW LETTERS
1996; 77 (2): 290-293
View details for Web of Science ID A1996UV48000022
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Observations of viscoelastic instabilities in recirculation flows of Boger fluids
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1996; 64 (2-3): 141-155
View details for Web of Science ID A1996UY49300002
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The conformation of semi-rigid polymers during flow through a fixed fiber bed
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1996; 64 (2-3): 95-140
View details for Web of Science ID A1996UY49300001
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Purely elastic instabilities in viscometric flows
ANNUAL REVIEW OF FLUID MECHANICS
1996; 28: 129-185
View details for Web of Science ID A1996TR81500005
- Screening Length for Suspended Fibers 1996
- An experimental investigation of the sedimentation of a dilute fiber suspension Phys. Rev. Lett. 1996; 2 (77): 290-293
- Viscoelastic instabilities in recirculation flows of Boger fluids J. Non-Newtonian Fluid Mech. 1996; 65: 141-155
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The rheology of non-dilute films of flexible, tethered chains by direct simulation
XIIth International Congress on Rheology
UNIV LAVAL, DEPT MECH ENGN. 1996: 323–323
View details for Web of Science ID 000089787000185
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A theoretical and experimental study of purely elastic instabilities in eccentric cylinder flows
XIIth International Congress on Rheology
UNIV LAVAL, DEPT MECH ENGN. 1996: 393–394
View details for Web of Science ID 000089787000217
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Rheology and kinetic theory of flowing fiber suspensions from dilute through semi-dilute concentrations
XIIth International Congress on Rheology
UNIV LAVAL, DEPT MECH ENGN. 1996: 588–589
View details for Web of Science ID 000089787000336
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A NONLOCAL THEORY FOR STRESS IN BOUND, BROWNIAN SUSPENSIONS OF SLENDER, RIGID FIBERS
JOURNAL OF FLUID MECHANICS
1995; 296: 271-324
View details for Web of Science ID A1995RR22000009
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ON PURELY ELASTIC INSTABILITIES IN ECCENTRIC CYLINDER FLOWS
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1995; 56 (3): 349-360
View details for Web of Science ID A1995QQ22200007
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THE EFFECT OF HYDRODYNAMIC INTERACTIONS ON THE ORIENTATION DISTRIBUTION IN A FIBER SUSPENSION SUBJECT TO SIMPLE SHEAR-FLOW
PHYSICS OF FLUIDS
1995; 7 (3): 487-506
View details for Web of Science ID A1995QH87100005
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Derivation of the nonlocal stress in bound, Brownian suspensions of slender, rigid fibers
NATO Advanced Study Institute on Mobile Particulate Systems
KLUWER ACADEMIC PUBL. 1995: 161–172
View details for Web of Science ID A1995BE53U00011
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OBSERVATIONS OF POLYMER CONFORMATION DURING FLOW-THROUGH A FIXED FIBER BED
JOURNAL OF FLUID MECHANICS
1994; 281: 319-356
View details for Web of Science ID A1994QA87300013
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A NUMERICAL STUDY OF HEAT AND MASS-TRANSPORT IN FIBER SUSPENSIONS
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
1994; 447 (1929): 77-110
View details for Web of Science ID A1994PQ29500006
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STUDY OF SILICON ETCHING IN CF4 O-2 PLASMAS TO ESTABLISH SURFACE REEMISSION AS THE DOMINANT TRANSPORT MECHANISM
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
1994; 12 (5): 2952-2962
View details for Web of Science ID A1994PM72400014
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THE EXTENSIONAL VISCOSITY AND EFFECTIVE THERMAL-CONDUCTIVITY OF A DISPERSION OF ALIGNED DISKS
PHYSICS OF FLUIDS
1994; 6 (6): 1955-1962
View details for Web of Science ID A1994NQ06900005
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OBSERVATIONS OF PURELY ELASTIC INSTABILITIES IN THE TAYLOR-DEAN FLOW OF A BOGER FLUID
JOURNAL OF FLUID MECHANICS
1994; 262: 27-73
View details for Web of Science ID A1994ND14300002
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A numerical study of the effective transport properties of short fiber suspensions
1995 NSF Design and Manufacturing Grantees Conference
SOC MANUFACTURING ENGINEERS. 1994: 487–488
View details for Web of Science ID A1994BG45A00239
- A Study of Silicon Etching in CF4 / O2 to Establish Surface Re-emission as the Dominant Transport Mechanism J. Vac. Sci. Tech. 1994; 5 (B 12): 2952-2962
- The Effects of Fluid Rheology on the Elastic Taylor-CouetteInstability J. Non-Newtonian Fluid Mech. 1994; 51: 195-225
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EFFECT OF SURFACE REEMISSION ON THE SURFACE-ROUGHNESS OF FILM GROWTH IN LOW-PRESSURE CHEMICAL-VAPOR-DEPOSITION
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS
1993; 11 (3): 557-568
View details for Web of Science ID A1993LD99700016
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EXPERIMENTAL STUDIES OF THE ONSET OF OSCILLATORY INSTABILITY IN VISCOELASTIC TAYLOR-COUETTE FLOW
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
1993; 46 (2-3): 315-330
View details for Web of Science ID A1993KZ99300010
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POLYMER STRETCH IN DILUTE FIXED-BEDS OF FIBERS OR SPHERES
JOURNAL OF FLUID MECHANICS
1992; 244: 17-54
View details for Web of Science ID A1992JZ76000002
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THE EFFECTS OF INERTIA ON THE VISCOELASTIC DEAN AND TAYLOR-COUETTE FLOW INSTABILITIES WITH APPLICATION TO COATING FLOWS
PHYSICS OF FLUIDS A-FLUID DYNAMICS
1992; 4 (11): 2415-2431
View details for Web of Science ID A1992JV12400011
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SIMULATION OF PROFILE EVOLUTION IN SILICON REACTIVE ION ETCHING WITH REEMISSION AND SURFACE-DIFFUSION
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
1992; 10 (3): 1091-1104
View details for Web of Science ID A1992HZ48500008
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AVERAGED-EQUATION AND DIAGRAMMATIC APPROXIMATIONS TO THE AVERAGE CONCENTRATION OF A TRACER DISPERSED BY A GAUSSIAN RANDOM VELOCITY-FIELD
PHYSICS OF FLUIDS A-FLUID DYNAMICS
1992; 4 (5): 887-894
View details for Web of Science ID A1992HQ71900005
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A PURELY ELASTIC INSTABILITY IN DEAN AND TAYLOR-DEAN FLOW
PHYSICS OF FLUIDS A-FLUID DYNAMICS
1992; 4 (3): 524-543
View details for Web of Science ID A1992HE35000010
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THE EFFECTS OF GAP WIDTH AND DILUTE-SOLUTION PROPERTIES ON THE VISCOELASTIC TAYLOR COUETTE INSTABILITY
JOURNAL OF FLUID MECHANICS
1992; 235: 285-317
View details for Web of Science ID A1992HF76500012
- The Effects Finite Gap and Dilute Solution Properties on the Viscoelastic Instability in Taylor-Couette Flow J. Fluid Mech. 1992; 5 (45): 477
- Polymer Configuration During Flow Through a Fixed Bed of Fibers edited by Moldenauers, P., Keunings, R. 1992
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OBSERVATIONS OF AXISYMMETRICAL TRACER PARTICLE ORIENTATION DURING FLOW THROUGH A DILUTE FIXED-BED OF FIBERS
PHYSICS OF FLUIDS A-FLUID DYNAMICS
1991; 3 (11): 2516-2528
View details for Web of Science ID A1991GL82900005
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VISCOELASTIC POISEUILLE FLOW THROUGH A CURVED CHANNEL - A NEW ELASTIC INSTABILITY
PHYSICS OF FLUIDS A-FLUID DYNAMICS
1991; 3 (9): 2043-2046
View details for Web of Science ID A1991GD54500003
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VISCOELASTIC POISEUILLE FLOW THROUGH A CURVED CHANNEL - A NEW ELASTIC INSTABILITY
PHYSICS OF FLUIDS A-FLUID DYNAMICS
1991; 3 (7): 1691-1694
View details for Web of Science ID A1991GM59400002
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SCREENING IN SEDIMENTING SUSPENSIONS
JOURNAL OF FLUID MECHANICS
1991; 224: 275-303
View details for Web of Science ID A1991FG99100015
- Simulation of Reactive Ion Etching with Surface Re-emission 1991
- Reverse RIE Lag in Oxide Etching 1991
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THE AVERAGE ROTATION RATE OF A FIBER IN THE LINEAR FLOW OF A SEMIDILUTE SUSPENSION
PHYSICS OF FLUIDS A-FLUID DYNAMICS
1990; 2 (12): 2093-2102
View details for Web of Science ID A1990EM49800003
- A Purely Elastic Instability in Taylor-Couette Flow J.Fluid Mech. 1990; 218: 573-600
- The Effect of Mask Erosion on Process Latitudes in Bi-Layer Lithography 1990
- Orientational Dispersion of Fibers in Extensional Flows Phys. Fluids A 1990; 7 (2): 1077
- The Hydrodynamic Stress in a Suspension of Rods Phys. Fluids A 1990; 1 (2): 7
- Simulation of Reactive Ion Etching Pattern Transfer J. Appl.Phys. 1989; 10 (66): 4664
- Simulation of Etching Profiles and Process Latitudes for the O2 Reactive Ion Etching Pattern Transfer Step in Multilevel Lithography 1989
- Factors Controlling the Etching Rate and Process Latitudes of the O2 Reactive Ion Etching Pattern Transfer Step in Multilevel Lithography Polymer Eng. Sci. 1989; 13 (29): 878
- A Kinetic Theory of Bombardment-Induced Interface Evolution J.Vac. Sci. Tech. 1989; 6 (B 7): 1488
- Application of the Kinetic Theory of Bombardment-Induced Interface Evolution to the Pattern Transfer Step in Multi-Layer Lithography 1989
- The Instability of a Dispersion of Sedimenting Spheroids J. FluidMech. 1989; 209: 521
- The Stability of a Falling Viscoelastic Film at Lowto Moderate Reynolds Numbers J. Non-Newtonian Fluid Mech. 1989; 31: 87
- A Purely Elastic Transition in Taylor-Couette Flow Rheol.Acta 1989; 28: 499
- Heat and Mass Transport in Composites of Aligned Slender Fibers Phys. Fluids 1989; 1 (1): 3
- A Non-Local Theory for the Heat Transport in Composites Containing Highly Conducting Fibrous Inclusions Phys. Fluids 1988; 31: 2405
- The Combined Effects of Hydrodynamic Interactions and Brownian Motion on the Orientation of Axisymmetric Particles Flowing Through Fixed Beds Phys. Fluids 1988; 31: 2769
- The Effects of Hydrodynamic Interactions on the Orientation ofAxisymmetric Particles Flowing Through a Fixed Bed of Spheres or Fibers Phys. Fluids 1988; 31: 728
- The Effective Thermal Conductivity and Elongational Viscosity of a Non-Dilute Suspension of Aligned Slender Rods Phys. Fluids 1988; 31: 1841
- Nonlocal Transport Models of the Self-Consistent Potential Distribution in a Plasma Sheath with Charge Transfer Collisions J. Appl. Phys. 1988; 64: 6200
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ENHANCED SEDIMENTATION IN VESSELS WITH INCLINED WALLS - EXPERIMENTAL-OBSERVATIONS
PHYSICS OF FLUIDS
1987; 30 (7): 1905-1914
View details for Web of Science ID A1987J272800003
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THE EFFECTS OF INERTIA ON THE STABILITY OF THE CONVECTIVE FLOW IN INCLINED PARTICLE SETTLERS
PHYSICS OF FLUIDS
1987; 30 (4): 960-973
View details for Web of Science ID A1987G960300006
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THE EFFECTS OF INERTIA ON THE BUOYANCY-DRIVEN CONVECTION FLOW IN SETTLING VESSELS HAVING INCLINED WALLS
PHYSICS OF FLUIDS
1986; 29 (12): 3935-3948
View details for Web of Science ID A1986F255000007
- Effect of Elasticity on the Mixing Torque Requirements for Rushton Turbine Impellers A.I.Ch.E. J. 1984; 30: 485