Article
Chemistry, Multidisciplinary
Caiting He, Qiushi Wang, Xiaoya Jia, Jie Liu, Runjun Sun, Meiyu Chen
Summary: In this study, conductive SiO2@Ag core-shell microspheres were synthesized and their properties were evaluated. Two-phase STFs were prepared using SiO2 and SiO2@Ag as dispersed phases, and their rheological properties were investigated. The results showed that the core-shell microspheres with the most uniform coating and lowest conductivity were achieved when the concentration of sodium hydroxide and glucose were 0.07 and 0.09 mol L-1, respectively. The two-phase STFs exhibited good shear thickening behaviors and the thickening rate reached 325% when the mass fraction of SiO2 and SiO2@Ag core-shell microspheres was 45% and 20%, respectively. This study presents a novel strategy for synthesizing conductive STFs for strain-sensing flexible stab-resistant composites.
Article
Computer Science, Interdisciplinary Applications
Simon F. Schoeller, Adam K. Townsend, Timothy A. Westwood, Eric E. Keaveny
Summary: This study addresses the challenges of simulating the motion and deformation of flexible filaments by using quaternions for kinematics, implicit time integration to alleviate numerical stiffness, and quasi-Newton methods for solving nonlinear equations. The framework has been shown to work with different models and methods, and can be applied to low Reynolds number hydrodynamic interactions.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Polymer Science
Mahdi Boudaghi, Brian J. J. Edwards, Bamin Khomami
Summary: The temporal and spatial evolution of shear banding in polyethylene solutions was studied during startup and steady-state shear flow. A high-fidelity method was developed to simulate and evaluate this phenomenon. The study observed transient shear banding during startup flow, with inhomogeneous concentration distribution within the system.
Article
Mechanics
Patrick J. McCauley, Christine Huang, Lionel Porcar, Satish Kumar, Michelle A. Calabrese
Summary: The study examines the formation and evolution of a heterogeneous flow and flow reversal in highly elastic, gel-like wormlike micelles (WLMs) formed from an amphiphilic triblock poloxamer P234 in 2M NaCl. The results show that these WLMs have a yield stress and exhibit viscoelastic aging, similar to some soft glassy materials. It is also found that these poloxamer WLMs undergo a period of strong elastic recoil and flow reversal after the onset of shear startup. The features of this flow heterogeneity are reminiscent of those for aging yield stress fluids and provide new insights into spatially heterogeneous flows in complex fluids.
JOURNAL OF RHEOLOGY
(2023)
Article
Mechanics
Shweta Sharma, V Shankar, Yogesh M. Joshi
Summary: This study analyzes the transient dynamics of viscoelastic flows during shear start-up, focusing on the onset of shear banding using different models and methods. The results suggest that there is no universal connection between the overshoot and subsequent decay of shear stress and the unstable eigenvalues obtained from stability analysis, making it difficult to predict transient shear banding based solely on shear stress behavior. Additionally, the study highlights the importance of considering factors that may affect the transient phenomena observed during shear start-up.
JOURNAL OF RHEOLOGY
(2021)
Article
Multidisciplinary Sciences
Hongyun Wang, Cheng Bi, Yongju Zhang, Axiang Ji, Pengyuan Qiu
Summary: Experimental study on the transient behavior of a magnetorheological brake excited by step currents under compression-shear mode reveals that the rising time of transient torque is significantly affected by rotational speed, compressive speed, and compressive strain position. The falling time of the transient torque, on the other hand, is independent of the amplitude of the applied current and compressive speed, but is influenced by rotational speed. The results emphasize the importance of considering these factors in the design and control of magnetorheological brakes under compression-shear mode.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
Brato Chakrabarti, Michael J. Shelley, Sebastian Furthauer
Summary: This study discovers a distinct mechanism for the transition of active particles into a state of collective motion at high density, leading to the formation of stationary chimera patterns. In addition, it reveals the existence of oscillatory flows and robust unidirectional pumping states under confinement, which can be selectively controlled. These findings provide important insights for the design of new active materials.
PHYSICAL REVIEW LETTERS
(2023)
Article
Engineering, Chemical
Alfredo Bosco, Felipe Paiva, Stefan Odenbach, Veronica Calado
Summary: This study investigated the preparation conditions of suspensions of precipitated calcium carbonate particles and found that samples with rosette PCC particles exhibited stronger shear thickening behavior. Acicular PCC particles also shear thickened at lower shear rates compared to rosette PCC particles.
ADVANCED POWDER TECHNOLOGY
(2021)
Article
Chemistry, Physical
Rodrigo C. Coelho, Nuno A. M. Araujo, Margarida M. Telo da Gama
Summary: The dynamics of nutrient mixing in bacterial colonies and other active nematics are complex due to the coupling between nutrients concentration and velocity field. The dispersion of the conserved activity field is found to be subdiffusive, hindered by a barrier of negative defects at the active-passive interface.
Article
Polymer Science
Vladimir Shelukhin
Summary: The new mathematical model developed for rotational sedimentation of particles in a concentric-cylinder Couette geometry shows good agreement with known measurement data, validating its accuracy. Sedimentation is proven to occur due to particles' rotation and rotational diffusion according to the proposed theory.
Article
Chemistry, Physical
Paulo C. F. da Camara, Liszt Y. C. Madruga, Nivia do N. Marques, Rosangela C. Balaban
Summary: The study demonstrates that PVP-based water-based drilling fluids can provide stable rheological parameters under high temperature and high pressure conditions, with good filtration performance and rheological properties.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Polymer Science
Ethan E. O'Banion, S. Shams Es-haghi
Summary: The rheological behavior of cellulose nanofibril (CNF) suspensions with different fines contents and solid concentrations was investigated. The samples showed a gel-like behavior with the highest dynamic moduli observed in samples with 50% fines. CNF suspensions with higher concentrations exhibited higher viscosity and dynamic moduli. A critical shear rate of 10 s-1 was found, above which viscosity measurements converged and below which they diverged. Yield stress decreased and then reached a plateau as fines levels increased. The lowest structure recovery was observed in samples with 50% fines content. A rheopectic-thixotropic transition was observed in samples with high fines content at low solid concentrations.
Article
Mechanics
Jonathan B. Freund
Summary: Numerical simulations were conducted to investigate the dynamics, transport, and equilibrium behaviors of a neutrally buoyant circular object in an active suspension within a larger circular container. The introduction of the object enhanced the suspension activity, inducing a corresponding correlated active-stress response and resulting in attraction or repulsion towards the container wall depending on the suspension activity strength. Moreover, a persistent propagating behavior was observed for moderate activity strength, providing a mechanism for long-range transport. When the activity strength was weak, the object's mobility was essential for supporting suspension instability and sustaining flow, but flow terminated when its mobility was diminished near the container wall.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
John F. Brady
Summary: A new continuous perspective for phoretic motion applicable to particles of any shape in 'microstructured' fluids has been developed, explaining how the local osmotic pressure of solute adjacent to the phoretic particle generates a thrust force. The study covers passive Brownian bath particles in suspension and active particles with characteristic speed and run length variations, showing that phoretic motion arises from a gradient in swim pressure of active matter.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
Qinglei Zeng, Tao Wang, Shengxin Zhu, Hao-sen Chen, Daining Fang
Summary: In this work, a phase-field model is proposed to simulate dynamic shear band formation and successfully captures the nucleation of shear bands. The capability of the model in capturing shear band formation in various scenarios is validated through strain-based and stress-based criteria.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Mechanics
Zhongyu Zheng, Xinliang Xu, Yuren Wang, Yilong Han
Summary: This study investigated the hydrodynamic interactions of two colloidal ellipsoids sediment in channels, revealing the critical role of confinement extent and particle shape anisotropy in anomalous hydrodynamic and diffusive behaviors. The findings suggest that negative rotation-rotation coupling and positive translation-rotation coupling are key characteristics of ellipsoid interactions. Additionally, a simple model proposed in this study has successfully reproduced some coupling phenomena observed between the ellipsoids, further confirmed by low-Reynolds-number hydrodynamic simulation.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Thermodynamics
Gudlavalleti V. V. S. Vara Prasad, Purbarun Dhar, Devranjan Samanta
Summary: In this article, a novel method of increasing the dynamic Leidenfrost temperature (T-DL) by adding surfactants to water droplets was proposed and experimentally studied. The effects of Weber number (We), Ohnesorge number (Oh), and surfactant concentration on T-DL were examined, and a scaling relationship was proposed. The findings have significant implications for thermal management systems operating at high temperatures.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Multidisciplinary Sciences
Shashank Kamdar, Seunghwan Shin, Premkumar Leishangthem, Lorraine F. Francis, Xinliang Xu, Xiang Cheng
Summary: The natural habitats of microorganisms in the human microbiome, ocean and soil ecosystems are full of colloids and macromolecules. Such environments exhibit non-Newtonian flow properties, which drastically affect the locomotion of microorganisms. Our understanding of bacterial motility in complex non-Newtonian fluids is still not as advanced as it is in simple Newtonian fluids. This study shows that flagellated bacteria in dilute colloidal suspensions display similar motile behaviors as those in dilute polymer solutions, revealing a universal particle-size-dependent motility enhancement and suppression of bacterial wobbling. A physical model incorporating the colloidal nature of complex fluids explains bacterial wobbling dynamics and mobility enhancement in both colloidal and polymeric fluids. These findings contribute to the understanding of bacterial motility in complex fluids and have implications in microbiological processes and bacterial engineering in complex environments.
Article
Chemistry, Physical
Yiming Qiao, Xiaolei Ma, Zhengyang Liu, Michael A. Manno, Nathan C. Keim, Xiang Cheng
Summary: The addition of Janus particles to particle-laden fluid interfaces can greatly enhance the stability and elasticity of the interfaces. This enhancement is attributed to the formation of local particle clusters surrounding each Janus particle.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2022)
Article
Thermodynamics
Somenath Gorai, Sarit K. Das, Devranjan Samanta
Summary: This article discusses the numerical simulation results of laminar mixed convection flow in vertical tubes, comparing the thermal and hydrodynamic features of buoyancy-assisted and opposed flows. The study finds that the variation of heat flux leads to unique velocity profiles and temperature gradients. The dependency of Reynolds and Richardson numbers on hydrodynamic and thermal features is also studied, providing correlations for fully developed friction factor and Nusselt number.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Biochemical Research Methods
Yiming Qiao, Zixue Ma, Clive Onyango, Xiang Cheng, Kevin D. Dorfman
Summary: By subjecting T4 DNA to shear in a cone-and-plate rheometer, researchers observed significant fragmentation and molecular weight changes, highlighting the importance of DNA manipulation in microfluidic devices.
Article
Chemistry, Multidisciplinary
Gudlavalleti V. V. S. Vara Prasad, Harsh Sharma, Neelkanth Nirmalkar, Purbarun Dhar, Devranjan Samanta
Summary: This study presents a novel method of enhancing the dynamic Leidenfrost temperature (TDL) of droplets by dispersing stable nanobubbles in the fluid, and investigates the impact of impact velocity and nanobubble concentration on TDL.
Article
Mechanics
Gudlavalleti V. V. S. Vara Prasad, Mohit Yadav, Purbarun Dhar, Devranjan Samanta
Summary: This study reports that the addition of Al2O3 nanoparticles to water significantly increases the onset of dynamic Leidenfrost temperature (T-DL) and suppresses the overall Leidenfrost phenomenon on a heated substrate. The onset of T-DL delays with increasing nanoparticle concentration but decreases with an increase in impact Weber number. Colloid droplets exhibit vigorous spraying behavior due to nanoparticulate residue deposition and the residue changes the boiling behavior, preventing bubble coalescence and vapor layer formation. Scaling analysis of T-DL with impact Weber number explores the thermo-hydrodynamic behavior of impacting colloid droplets.
Article
Multidisciplinary Sciences
Yiyu Zhang, Da Wei, Xiaochen Wang, Boyi Wang, Ming Li, Haiping Fang, Yi Peng, Qihui Fan, Fangfu Ye
Summary: Microglia are resident macrophage cells in the central nervous system that migrate to search for pathogens or abnormal neural activities. This research reveals that microglia are promptly attracted by external forces, a behavior called mechanotaxis, which has not been confirmed in microglia before. The study also shows that microglial motion shares similarities with bacterial run-and-tumble motion, but with more sophistication, suggesting differences between eukaryotic and prokaryotic cells and their environments. This work provides a framework for studying immune cells exploring complex environments.
Article
Physics, Fluids & Plasmas
Benjamin C. Druecke, Ranit Mukherjee, Xiang Cheng, Sungyon Lee
Summary: This study combines experiments with theoretical modeling to investigate the failure modes of granular rafts without free periphery under compression. Unlike granular rafts with open periphery, the granular rafts in this study remain stable under finite compressive stresses. Interestingly, rafts made of small particles gradually sink by expelling individual particles under large compression, while rafts made of large particles collapse catastrophically by forming large-scale creases. The collective creasing is enhanced by the 2D particle density and is suppressed by the density difference of the two fluids. A one-dimensional continuum model is developed to provide quantitative explanations of the experimental findings.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Chemistry, Multidisciplinary
Yiming Qiao, Zhengyang Liu, Xiaolei Ma, Nathan C. Keim, Xiang Cheng
Summary: The formation of particle clusters can greatly affect the dynamics and mechanical properties of suspensions. By introducing self-assembled localized particle clusters at a fluid-fluid interface, it is found that particles within clusters experience lower shear-induced stretching compared to particles outside clusters. This heterogeneous dynamics increases the effective surface coverage of particles, thereby enhancing the shear moduli of the interface.
Article
Multidisciplinary Sciences
Gudlavalleti V. V. S. Vara Prasad, Purbarun Dhar, Devranjan Samanta
Summary: This article discusses the electrohydro-dynamics of non-Newtonian dielectric droplets impacting on superhydrophobic surfaces. The study examines the role of key parameters such as electric Eotvos number, Weber number, dielectric particle concentration, and polymer concentration. The findings reveal that the suppression of drop rebound on superhydrophobic surfaces occurs at lower electric Eotvos numbers due to the interplay of non-Newtonian effects and electric field. The introduction of the 'electro-elastic effect' explains the inhibition of drop rebound and the development of anti-superhydrophobicity.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Multidisciplinary Sciences
Yi Peng, Wei Li, Tim Still, Arjun G. G. Yodh, Yilong Han
Summary: In this study, researchers observed the coalescence of nuclei during the crystal-crystal transition using a colloidal system. They found that the coalescence process involves three stages: coupled growth of nuclei, their attachment, and relaxation of the coalesced nucleus. The kinetics of the process varies depending on the nucleus size, interface, and lattice orientation.
NATURE COMMUNICATIONS
(2023)
Article
Thermodynamics
Somenath Gorai, Devranjan Samanta, Sarit K. Das
Summary: This article investigates the development of pure turbulent mixed convection in a vertical tube and compares the hydrodynamic and thermal features of both buoyancy-assisted and opposed flows. The study found that the friction factor and Nusselt number are lower in the case of buoyancy-assisting flow compared to buoyancy-opposing flows. Similar friction factors and heat transfer trends were obtained at a given Grashof number. The entry length was also examined and found to be restricted by the length-to-diameter ratio for both flows.
HEAT TRANSFER ENGINEERING
(2023)
Article
Chemistry, Physical
Xiaolei Ma, Zhengyang Liu, Wei Zeng, Tianyi Lin, Xin Tian, Xiang Cheng
Summary: This study reports the formation of different crack patterns during the drying of bacterial suspensions. Circular cracks are observed for swimming Escherichia coli (E. coli) with active motility, while spiral-like cracks form for immotile bacteria. The mechanisms behind the formation of circular cracks are explored using elastic fracture mechanics and poroelastic theory.