Article
Chemistry, Multidisciplinary
Han Li, Zhi Xu, Chen Ma, Ming Ma
Summary: In this paper, the dependence of slip length for water on different supporting substrates and thickness of graphene layers is investigated using colloidal probe atomic force microscopy. The results provide reference values for the slip length of water on supported few-layer graphene and show that both the type of substrate and the thickness of graphene layers affect the slip length. Furthermore, it is observed that the slip length decreases with increasing temperature.
Article
Engineering, Environmental
Shaofan He, Zhongpeng Zhu, Bo Zhang, Ye Tian
Summary: By adjusting the intrinsic composition and surface roughness, the intrinsic wetting boundary and critical roughness value of super-wettability on silicon nanowire surfaces were systematically studied. With the defined critical f value and surface structure determined CRV, long-lasting superhydrophilicity and superhydrophobicity were achieved.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Energy & Fuels
C. Liu, Y. Li, Z. Zhou, P. Wisniewski
Summary: The article analyzes the effects of cascade surface roughness on boundary layer flow, showing that the total pressure loss coefficient of the cascade decreases first and then increases with the increase of roughness, and the roughness has a significant impact on cascade loss. Additionally, the separation bubbles decrease with the increase of roughness, leading to a reduction in cascade loss.
FRONTIERS IN ENERGY RESEARCH
(2022)
Article
Engineering, Chemical
Qingjun Du, Peng Zhou, Yuping Pan, Xiao Qu, Lu Liu, Hui Yu, Jian Hou
Summary: Hydrophobicity and roughness of solid surfaces play crucial roles in determining wetting and flow behavior. Increasing roughness can enhance apparent hydrophilicity in some cases, while it may improve apparent hydrophobicity in others. Beyond the superhydrophobic boundary, the effect of roughness on apparent hydrophobicity weakens or disappears.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Mechanical
Vimal Edachery, R. Shashank, Satish Kailas
Summary: The study highlights the influence of surface texture directionality and roughness on lubricant wettability, showing that wettability varies with roughness and that directionality parallel to sliding direction improves entrapment capability. Surfaces with individual entrapment sites exhibit better lubricant entrapment capability in near Wenzel mixed-wetting conditions.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Construction & Building Technology
Jiayun Xu, Biao Ma, Shulin Zhou, Weijie Mao, Xiaoqing Wang
Summary: Based on the Wenzel model and Cassie model, this paper established a new wetting model for irregular rough surfaces and calculated the wetting depth and apparent contact angle. The experimental results showed significant differences in the surface texture parameters of different aggregates. The relative error between the predicted and measured contact angles was less than 15%, indicating excellent prediction effect. The wetting model analysis revealed that the surface tension of the test liquid, lithology of the solid aggregate, surface roughness, and texture structure are important control parameters affecting wetting.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Mining & Mineral Processing
Ming Li, Yaowen Xing, Chunyun Zhu, Qinshan Liu, Zili Yang, Rui Zhang, Youfei Zhang, Yangchao Xia, Xiahui Gui
Summary: This study introduces a measurement of wetting film thinning to investigate the wettability and floatability of solid surfaces with varying roughness. The wetting property is quantified using contact angle measurement and dynamic force microbalance test, while the floatability is studied through observation of dynamic attachment between bubbles and solid surfaces and induction time measurement. The results show that the contact angle decreases and the adhesion force increases with increasing surface roughness. In contrast, hydrophobized surfaces exhibit increasing contact angles and decreasing adhesion strength.
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Yu Qiu, Ke Xu, Amir A. Pahlavan, Ruben Juanes
Summary: This article studies the immiscible fluid-fluid displacement on a precisely controlled structured surface in a microfluidic device, serving as an analogue for rough fractures. It is found that surface roughness affects the wetting transition and film formation, leading to different morphologies of undisplaced fluid. The implications of these observations for geologic and technological applications are discussed.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Energy & Fuels
Shangning Wang, Di Xiao, Shuyi Qiu, Xuan Zhang, Xuesong Li, David L. S. Hung, Min Xu
Summary: The taper angle of an injector has a significant influence on spray behavior, but current studies mostly focus on the spray morphology, neglecting the study of in-nozzle process and influencing mechanism. This study investigates the impact of taper angles on spray characteristics using backlit imaging method on two-dimensional optical nozzles. The results show that the design of the taper angle affects the in-nozzle pressure distribution and results in different bubbling characteristics, as well as changes the contact mechanism between phase boundary and counterbore surface.
Article
Engineering, Civil
Jiabiao Wang, Jianshi Zhao, Tongtiegang Zhao, Hao Wang
Summary: This paper presents a method to partition the uncertainty sources of flood routing, showing that each source has unique effects on flood routing and the contribution ratios vary significantly with time and space.
JOURNAL OF HYDROLOGY
(2022)
Article
Chemistry, Physical
Guillaume Espy, Jannick Duchet-Rumeau, Sebastien Livi, Olivier Lhost, Jean-Francois Gerard
Summary: This paper describes a simple wetting model based on the balance between liquid pressure and surface tension to understand the parameters required for achieving slippery superhydrophobicity. The importance of both nano and micro-scale texturing for superhydrophobicity is discussed, and the stability limits of a Cassie-Baxter interface are studied. The proposed model provides insights into the design of stable superhydrophobic surfaces.
SURFACES AND INTERFACES
(2023)
Article
Engineering, Mechanical
Mahendra Prasad
Summary: This paper derives an analytical expression for the friction factor of a two-dimensional semicylindrical roughness using Navier-Stokes equation and mixing length theory. It compares this expression with the modified series mathematical representation of Haalands equation for friction factor.
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2022)
Article
Nanoscience & Nanotechnology
Samuel Griffith, Fateeha Nisar Siddiqui, Guido Schmitz
Summary: In this study, the advancing contact angles of the Sn-(l)/Cu-(s) reactive solder system were investigated to understand their dependencies on surface roughness and droplet size. It was observed that there are clear size dependencies for both smooth and rough substrates, but interestingly, the trends are inverted. The inversion of the size dependence of the wetting angle is discussed based on the triple line pinning phenomenon, Wenzel's wetting model, and the consumption of Sn by a solder reaction. Quantitative models are proposed to better understand size dependencies on rough and smooth surfaces, and larger pinning barriers are determined for rougher substrates.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Mechanics
Hangyu Zhu, Chong Pan, Guohua Wang, Yirui Liang, Xiaocang Ji, Jinjun Wang
Summary: Experimental investigation on particle clustering in a particle-laden turbulent boundary layer with moderate frictional Reynolds number (Re-tau = 5500) reveals self-similarity of particle cluster geometries in the log layer, characterized by power law of the probability density functions of cluster areas and y-scaling of their moments. A conceptual model is proposed where particle clusters tend to reside on back ridges of low-momentum attached u-structures, influenced by high-strain from converging sweep-ejection events. Conditional statistics show sand grains with small slip velocities are captured by low-momentum turbulent motions to form clusters.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
W. Liu, G. E. Lau, K. Ngan
Summary: Scale-dependent turbulence statistics were calculated for large-eddy simulations of flow over square and staggered obstacle arrays. The results show that different array types can affect the characteristics of energy spectra and transfer spectra, while mean lengthscales are insensitive to array type and horizontal position.
Article
Biophysics
Aleksey Belyaev
Summary: The blood glycoprotein VWF responds to hydrodynamic stresses by changing its conformation, with its mechanical properties controlled by pH-dependent interactions within dimeric subunits. Computer simulations show that interactions between different domains of VWF affect the protein's ability to resist shear stress and compact in non-sheared fluid.
BIOPHYSICAL JOURNAL
(2021)
Article
Mechanics
Anass Bouchnita, Aleksey Belyaev, Vitaly Volpert
Summary: This study addresses the physical and biochemical effects during thrombosis in aneurysms and recirculation zones, using a continuum description and partial differential equation-based model to account for fluid dynamics, platelet transport, adhesion and aggregation, and biochemical cascades of plasma coagulation. The research focuses on the role of blood cell transport and accumulation, including interactions between platelets and red blood cells, as well as the impact of hematocrit-dependent blood rheology on the growth of aneurysmal thrombus.
Article
Mechanics
Evgeny S. Asmolov, Tatiana V. Nizkaya, Jens Harting, Olga I. Vinogradova
Summary: This theoretical study demonstrates that particles in a shear flow may experience instability in their equilibrium positions due to inertial effects and the Saffman lift force. The critical Stokes number determining the onset of unstable equilibrium is derived, and lattice Boltzmann simulations for spherical particles and prolate spheroids are conducted to validate the analysis. The research provides a simple explanation for previously observed unusual phenomena in experiments and computer simulations.
Article
Mechanics
Evgeny S. Asmolov, Tatiana Nizkaya, Olga Vinogradova
Summary: Catalytic Janus swimmers exhibit diffusiophoretic motion by generating gradients of concentrations and electric potential spontaneously. This study considers the experimentally relevant scenario of particles releasing both types of ions and derives a simple expression for particle velocity in the limit of a thin electrostatic diffuse layer. The approximate expression remains highly accurate even in the presence of large ion fluxes and surface potentials, and it offers explanations for several intriguing phenomena, such as the reversal of particle motion in response to variations in the salt concentration or the self-diffusiophoresis of uncharged particles.
Correction
Mechanics
Anass Bouchnita, Aleksey V. Belyaev, Vitaly Volpert
Article
Mathematics
Evgeny S. Asmolov, Tatiana Nizkaya, Olga Vinogradova
Summary: In this study, we have derived a non-linear outer solution for the electric field and concentrations of catalytic swimmers with any shape, and determined the velocity of particle self-propulsion. Our approach allows us to include the complicated effects of anisotropy and inhomogeneity of surface ion fluxes, leading to more accurate calculations.
Review
Chemistry, Physical
Tatiana Nizkaya, Evgeny S. Asmolov, Olga Vinogradova
Summary: Self-propelling particles or microswimmers, as ideal model objects for experimental studies and applications, have attracted significant attention. This article summarizes recent advances in the theoretical description of the self-propulsion of catalytic microswimmers that non-uniformly release ions, focusing on nonlinear effects and geometric tuning.
CURRENT OPINION IN COLLOID & INTERFACE SCIENCE
(2022)
Article
Biophysics
Aleksey V. Belyaev, Yulia K. Kushchenko
Summary: Platelet adhesion and activation are crucial initial processes in arterial and microvascular hemostasis, hindered by high bloodflow forces. von Willebrand factor (VWF), a blood plasma protein, plays a key role in the mechanochemical regulation of shear-induced platelet aggregation (SIPA). Recent studies have shown that mechanical tension on the extracellular part of glycoprotein receptor GPIb can trigger biochemical reactions in platelets, leading to integrin alpha IIb beta 3 activation and strengthened adhesion. Computer simulations of platelet adhesion to surface-grafted VWF multimers in pressure-driven flow show that GPIb-mediated mechanotransduction is a feasible way of platelet activation and aggregation under high shear stress. A quantitative understanding of mechanochemical processes involved in SIPA could lead to the discovery of new anti-platelet medication and the development of numerical models for platelet thrombosis and hemostasis.
BIOMECHANICS AND MODELING IN MECHANOBIOLOGY
(2023)
Article
Mechanics
Olga Vinogradova, Elena F. Silkina, Evgeny S. Asmolov
Summary: This article revisits the theory of electrokinetic ion transport in cylindrical channels of a fixed surface charge density. It focuses on the impact of hydrophobic slippage and mobility of adsorbed surface charges. The paper formulates generalized Onsager relations for cylinders of arbitrary radii and derives exact expressions for mean electro-osmotic mobility and conductivity. The theory provides a simple explanation for the giant enhancement of electrokinetic mobility and conductivity of hydrophobic nanotubes.
Article
Engineering, Biomedical
Noel G. Tsyu, Aleksey V. Belyaev
Summary: A multi-subunit glycoprotein called Von Willebrand factor (VWF) in blood plasma is responsible for mediating platelet adhesion to damaged blood vessel walls. The adhesion of VWF to collagen is crucial for platelet hemostasis and thrombosis, acting as a molecular bridge between injury and platelet adhesion receptors. This study proposes a simulation framework for VWF-mediated platelet adhesion under the influence of shear flow, using particles representing VWF multimers and platelets immersed in a viscous fluid. The model considers the flattened platelet shape and balances detail of description with computational complexity.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING
(2023)
Article
Mechanics
Evgeny S. S. Asmolov, Olga I. I. Vinogradova
Summary: Catalytic Janus swimmers can propel themselves in electrolyte solutions by releasing active ions from their surface. We investigated the effect of passive ions from added salt on the self-propulsion of two types of swimmers: those that release only one type of ion (type I) and those that release equal amounts of cations and anions (type II). Our results showed that the maximum ion flux and propulsion velocity are constrained for type I swimmers, but remain unaffected for type II particles.
Review
Biophysics
Aleksey V. Belyaev, Irina V. Fedotova
Summary: This review examines recent experimental findings and theoretical insights about catch bonds between blood cells, as well as their role in platelet thrombosis and hemostasis.
BIOPHYSICAL REVIEWS
(2023)
Article
Chemistry, Physical
Olga I. Vinogradova, Elena F. Silkina
Summary: This paper revisits the phenomenon of conductivity in electrolyte solutions confined in micro- and nanochannels, focusing on the impact of salt concentration on ion mobility and subsequently on conductivity. A systematic treatment of ion electrophoresis is presented, yielding equations for their zeta potentials and mobilities. These mobilities are then used to derive a simple expression for bulk conductivity, valid in a concentration range up to a few molars and more accurate than previous theories. The formalism is extended to charged channels, providing equations for conductivity in different modes, accounting for the reduction in electrophoretic mobility with salt concentration. This analysis offers a framework for interpreting measurements of electrolyte solution conductivity in both bulk and narrow channels.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Chemistry, Physical
Olga I. Vinogradova, Elena F. Silkina, Evgeny S. Asmolov
Summary: This article discusses how the wettability of solid walls affects electrokinetic phenomena, highlighting the use of hydrophobic slippage and confinement effects to induce novel electrokinetic properties. However, the impact of slippage is greatly reduced if surface charges adsorbed on the wall migrate along the hydrophobic surface under an applied field.
CURRENT OPINION IN COLLOID & INTERFACE SCIENCE
(2023)
Article
Physics, Fluids & Plasmas
Olga Vinogradova, Elena F. Silkina, Evgeny S. Asmolov
Summary: Recent research has found that the ratio of electrostatic disjoining pressure to excess osmotic pressure near walls affects ion transport behavior in channels. In the thick channel regime, the channel acts like a thick one, suitable for highly charged channels, while in the thin channel regime, the channel behaves more like a thin channel, suitable for weakly charged channels.
