Article
Mechanics
Gloire Imani, Lei Zhang, Chao Xu, Munezero Ntibahanana, Hai Sun, Jun Yao
Summary: In this study, direct numerical simulations were conducted to compare the release conditions of finite droplets and long droplets in three-dimensional constrained channels. The results showed that for finite droplets, the maximum pressure increases with the increase in the contact angle, while for long droplets, the maximum pressure is almost the same in water-wet and neutral-wet conditions. The study also found that droplet size affects the release pressure, with the minimum release pressure of finite droplets increasing linearly with the droplet length in water-wet conditions, and the minimum release pressure of long droplets not changing much as the length increases. Furthermore, the release pressure decreases with the increased tapering angle.
Article
Chemistry, Physical
Nathan Vani, Sacha Escudier, Alban Sauret
Summary: This study investigates the mechanism of particle clogging in confined systems, focusing on bridging clogging. Experimental characterization of particulate suspensions flow through millifluidic devices at different concentrations was conducted, and the influence of solid fraction on clogging probability was discussed.
Review
Mechanics
S. Afiqah Wajihah, D. S. Sankar
Summary: This paper summarizes the research field of hemodynamics, including the flow characteristics of blood, the geometry of blood vessels, and the behavior of blood under normal and abnormal flow conditions. By discussing mathematical modeling and solution methods, the influence of these parameters on physiologically important flow quantities is understood. The study found that the impact of resistance on blood flow varies in different states, such as healthy, anemic, and diabetic, and severe arterial stenosis can result in inadequate blood supply to organs, leading to patient death. It is hoped that the results of this study can help predict blood behavior and flow in stenotic arteries, and provide valuable physiological information for treating cardiovascular diseases.
ARCHIVE OF APPLIED MECHANICS
(2023)
Article
Mechanics
Olukayode T. Majekodunmi, Sara M. Hashmi
Summary: The study reveals that colloidal clogging behavior varies in different geometric pore structures, with tapered pores showing unique statistical distribution characteristics compared to traditional parallel or series structures. The coexistence of Poisson and lognormal processes in tapered microchannels suggests a complex transient Markov process where clogs can occur independently and dependently on one another. This highlights the importance of considering geometric factors in understanding clogging dynamics.
Article
Mechanics
Mathieu Souzy, Alvaro Marin
Summary: The transport of non-cohesive suspensions through constrictions follows a "slower is faster" principle under pressure-controlled driving. The role of interparticle liquid flow and hydrodynamic forces in forming and stabilizing an arch blocking the particle transport through a constriction is crucial. Different liquid driving methods, such as volume-controlled systems and pressure-controlled systems, have different effects on the flow behavior.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Biochemical Research Methods
Noemi Renaudin, Charlie Demene, Alexandre Dizeux, Nathalie Ialy-Radio, Sophie Pezet, Mickael Tanter
Summary: Ultrasound localization microscopy (ULM) is a technique that allows localization and monitoring of cerebral blood flow at a small scale. By detecting the flow of injected microbubbles, ULM provides real-time information about brain activity at high spatiotemporal resolution.
Article
Mathematics
Amjad Ali, Muhammad Umar, Zaheer Abbas, Gullnaz Shahzadi, Zainab Bukhari, Arshad Saleem
Summary: This article presented an analysis of pulsatile flow of non-Newtonian micropolar fluid under Lorentz force in a channel with symmetrical constrictions. The study found that the Hartmann number effectively controlled the flow separation region, while the wall shear stress increased with Hartmann and Reynolds numbers, but decreased with the MP parameter. The micro-rotation velocity increased with Reynolds number and decreased with the MP parameter.
Article
Mechanics
Qingqing Gu, Jinggang Zhang, Haihu Liu, Lei Wu
Summary: In this study, three-dimensional simulations were conducted to investigate the behavior of drops in a constricted square capillary with non-uniform depth. The effects of various parameters on breakup and deformation were examined. It was found that the snap-off time t(b) exhibited a power-law relationship with the capillary number. However, the variation of the volume of the first daughter drop Vd with the capillary number was more complex, influenced by factors such as viscosity ratio and the presence of surfactants. Notably, the inclusion of surfactants helped homogenize the volume of the first daughter drop.
Article
Chemistry, Multidisciplinary
Niraj Kr Prasad, Siddhartha Sankar Ghosh, Amaresh Dalal
Summary: The study focuses on the deformation and breakup of a sheathinning finitely extensible nonlinear elastic-peterlin (FENE-P) drop moving through a constricted microchannel. The computational simulation shows that the drop deformation and breakup can be controlled by changing parameters such as channel confinement, Deborah number, solvent viscosity ratio, viscosity ratio, and capillary number. The findings provide valuable insights into the deformation and breakup patterns of drug carriers in constricted microcapillaries.
Article
Multidisciplinary Sciences
Fan Cui, Sophie Marbach, Jeana Aojie Zheng, Miranda Holmes-Cerfon, David J. Pine
Summary: This article investigates the DNA-mediated interactions between colloids and proposes a theoretical model to predict the molecular-level behavior of adhesion and melting. By combining experimental measurements and theoretical analysis, the study provides a quantitative and predictive approach for guiding material design with DNA nanotechnology.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Congping Chen, Zhentao She, Peng Tang, Zhongya Qin, Jufang He, Jianan Y. Qu
Summary: The study presented an approach for imaging neurovascular dynamics in live mouse cortices using multi-contrast mesoscopic and two-photon microscopic imaging, revealing the spatiotemporal correlation between neuronal and vascular responses. The research uncovered significant differences in NVC at regional and microvascular levels, as well as the impact of different brain states on NVC, particularly showing that anesthesia and sedation disrupt NVC.
Article
Engineering, Chemical
Cristina Gonzalez-Fernandez, Jenifer Gomez-Pastora, Eugenio Bringas, Maciej Zborowski, Jeffrey J. Chalmers, Inmaculada Ortiz
Summary: This study focuses on the separation and recovery of magnetic components in microdevice design, comparing the performance of two different types of devices. The results show that the micro-QMS can achieve more efficient particle retrieval, highlighting its potential role in the recovery of magnetic catalyst support materials.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2021)
Article
Multidisciplinary Sciences
B. G. H. Janssen, Y. M. Zhang, I Kosik, A. Akbari, C. W. McIntyre
Summary: Hemodialysis is a life-saving treatment for kidney failure, but it is associated with a high mortality rate due to cardiovascular disease. This study successfully developed a small animal model to assess the microvascular consequences of hemodialysis. The results showed that even in healthy animals, hemodialysis can cause disturbances in systemic hemodynamics and disrupt microvascular perfusion. This study highlights the importance of investigating hemodialysis-induced ischemic organ injury and potential interventions to reduce it.
SCIENTIFIC REPORTS
(2022)
Article
Mechanics
Yuqi Wei, Yi Chen, Jun Xu, Jie Li
Summary: This study presents a micromixer based on induced charge electro-osmosis with a conductive barrier plate, and investigates the effects of the installation of the conductive plate, the concentration of the polymer, and the shape of the conductive plate on the mixing efficiency. The results demonstrate that the use of a conductive plate significantly improves the mixing efficiency.
Article
Physics, Particles & Fields
Haryanto M. Siahaan
Summary: The paper presents a novel solution describing magnetized spacetime outside an electrically charged object with NUT parameter. The solution is obtained by applying Ernst magnetization to the Reissner-Nordstrom-Taub-NUT spacetime as a seed. After discussing some physical aspects, it is shown that the extremal entropy of a magnetized Reissner-Nordstrom-Taub-NUT black hole can be reproduced using the Cardy formula.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Biophysics
Sebastian J. Mueller, Franziska Weigl, Carina Bezold, Christian Baecher, Krystyna Albrecht, Stephan Gekle
Summary: In this study, a numerical model is proposed to simulate the deformation of biological cells in arbitrary three-dimensional flows, calibrated using experimental data and validated through comparison to previous experiments on different types of cells and particles.
BIOMECHANICS AND MODELING IN MECHANOBIOLOGY
(2021)
Article
Mechanics
Katharina Graessel, Christian Baecher, Stephan Gekle
Summary: This study investigates the influence of anisotropy on the Rayleigh-Plateau instability mechanism under various surface tension conditions. It reveals the significant impact of anisotropy on the dominant wavelength of instability, as well as the formation of satellite droplets under anisotropic tension. The research combines analytical linear stability analysis with numerical simulations to explore the effects of different tension scenarios on instability behavior.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Christian Baecher, Katharina Graessel, Stephan Gekle
Summary: This study examines the Rayleigh-Plateau instability of cylindrical vesicles and cell membranes under tension, considering the combined influence of anisotropic tension and membrane elasticity. The research shows that the combination of bending elasticity and tension anisotropy leads to three qualitatively different regimes for the Rayleigh-Plateau scenario, while shear elasticity and area dilatation only exhibit the classical and suppressed regimes.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Polymer Science
Soren Schumacher, Sanwardhini Pantawane, Stephan Gekle, Seema Agarwal
Summary: The synthesis and polymerization behavior of four different monofunctional vinyl cyclopropane (VCP) derivatives were investigated. The study found that different VCPs have varying abilities to form hydrogen bonds in their side chains, leading to preorganization and potentially faster polymerization. Although VCPs capable of hydrogen bonding did not show significant differences, a general effect of hydrogen bonds on polymerization behavior was observed.
Article
Hematology
Francois Yaya, Johannes Roemer, Achim Guckenberger, Thomas John, Stephan Gekle, Thomas Podgorski, Christian Wagner
Summary: The objective of the study was to investigate the flow field of plasma around red blood cells in capillary flow, with experimental results showing different flow fields around red blood cells of different shapes and vortex structures changing with the distance between cells.
Article
Polymer Science
Sanwardhini Pantawane, Stephan Gekle
Summary: In this study, atomistic and coarse-grained molecular dynamics simulations were used to investigate the conformation of a single poly(3-hexylthiopene) chain at different temperatures. It was found that bundle and toroid structures were predominantly present, with bundles becoming more abundant at lower temperatures. A comparison of atomistic and Martini-based coarse-grained models showed excellent agreement. Furthermore, the temperature dependence of P3HT was linked to that of simple Lennard-Jones model polymers in a vacuum. The addition of solvent (THF) resulted in a prominent swelling of the molecular size at around 220 K, which correlated well with experimental observations of increased frequency of bundle structures.
Article
Chemistry, Multidisciplinary
Chen Liang, Jun Young Cheong, Gabriel Sitaru, Sabine Rosenfeldt, Anna S. Schenk, Stephan Gekle, II-Doo Kim, Andreas Greiner
Summary: The study shows that, for citrate and polyvinylpyrrolidone stabilized gold nanoparticles, the reactivity increases with increasing particle diameter in the size range of 10-58 nm when the total surface area is kept constant. Furthermore, internal structural parameters such as defect tendency also play a significant role in catalytic activity.
ADVANCED MATERIALS INTERFACES
(2022)
Article
Computer Science, Interdisciplinary Applications
Gabriel Sitaru, Stephan Gekle
Summary: Multistep catalytic reactions using chemically incompatible catalysts were studied by immobilizing the catalysts on fibrous membranes. The efficiency of the reactions was investigated using three different methods. The results showed that although the efficiency decreased with increased flow speed, the total production still increased. Additionally, the spatial proximity of the catalysts had a positive effect on the reaction efficiency.
COMPUTERS & FLUIDS
(2022)
Article
Polymer Science
Soren Schumacher, Sanwardhini Pantawane, Stephan Gekle, Seema Agarwal
Summary: This study presents the synthesis of four different monofunctional vinyl cyclopropane amides and investigates their photopolymerization behavior. It is found that all the amides can form hydrogen bonds, with one being the amide linkage and the other being the side chain. The number of additional hydrogen bonds is regulated by different side chains. The study demonstrates that hydrogen bonds can preorganize the monomers and lead to fast polymerization.
MACROMOLECULAR CHEMISTRY AND PHYSICS
(2022)
Article
Biology
Richard Gerum, Elham Mirzahossein, Mar Eroles, Jennifer Elsterer, Astrid Mainka, Andreas Bauer, Selina Sonntag, Alexander Winterl, Johannes Bartl, Lena Fischer, Shada Abuhattum, Ruchi Goswami, Salvatore Girardo, Jochen Guck, Stefan Schruefer, Nadine Stroehlein, Mojtaba Nosratlo, Harald Herrmann, Dorothea Schultheis, Felix Rico, Sebastian Johannes Mueller, Stephan Gekle, Ben Fabry
Summary: This study presents a high-throughput, simple, and low-cost microfluidic method to quantitatively measure the elastic and viscous moduli of individual cells. By measuring cell deformation and rotation frequency, the frequency-dependent viscoelastic properties of cells can be determined, revealing the influence of cell cycle and physical interactions between different cell structures.
Article
Physics, Applied
Sebastian J. Mueller, Ben Fabry, Stephan Gekle
Summary: Bioprinting of living cells can lead to shape deformations, affecting cell survival and functionality. Extensional stresses occurring when cells leave the nozzle have been ignored. Lattice Boltzmann simulations and a finite-element based cell model were used to study cell deformation inside the nozzle and at its exit. Two simple methods were developed to predict maximum cell stress and approximate cell strains based on printing parameters.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Fluids & Plasmas
Steffen M. Recktenwald, Katharina Graessel, Yazdan Rashidi, Jann Niklas Steuer, Thomas John, Stephan Gekle, Christian Wagner
Summary: Constricted blood vessels in the circulatory system can cause complications by affecting the organization of red blood cells. In this study, the dynamics of a cell-free layer (CFL) in a constricted microchannel under steady and time-dependent flow conditions were examined. A image-processing routine was developed to analyze the CFL evolution under various flow conditions. The results showed that the concentration of red blood cells and the amplitude of the pressure signal had dominant effects on the CFL dynamics.
PHYSICAL REVIEW FLUIDS
(2023)
Article
Physics, Fluids & Plasmas
Moritz Lehmann, Mathias J. Krause, Giorgio Amati, Marcello Sega, Jens Harting, Stephan Gekle
Summary: This study evaluates the feasibility of using different precision optimization algorithms in lattice Boltzmann method and finds that the accuracy difference between FP32 and 16-bit precision can be neglected in most cases.
Article
Mathematics, Interdisciplinary Applications
Moritz Lehmann, Stephan Gekle
Summary: The plane-cube intersection problem and its iterative solutions have been extensively studied in computational fluid dynamics simulation. This study proposes an improved analytic solution for all intersection cases and compares it with the previous solution from Scardovelli and Zaleski. The authors also evaluate the performance and accuracy of different solutions on different hardware platforms, and discuss the application of PLIC-curvature calculation in free surface fluid simulations.
Article
Biophysics
Steffen M. Recktenwald, Katharina Graessel, Felix M. Maurer, Thomas John, Stephan Gekle, Christian Wagner
Summary: The dynamics and shape transitions of single red blood cells (RBCs) under confined and unsteady flow conditions were investigated using microfluidic experiments and numerical simulations. It was found that the transition time from the symmetric croissant to the off-centered, nonsymmetric slipper shape was faster than the opposite shape transition. Simulations showed that these dynamics depend on the orientation of the RBC membrane in the channel during the time-dependent flow. The tank-treading movement of slipper-shaped RBCs combined with the narrow channel led to oscillations of the cell's center of mass.
BIOPHYSICAL JOURNAL
(2022)