Article
Mathematics, Applied
Michal Benes, Petr Kucera, Petra Vackova
Summary: This paper investigates the existence and uniqueness of solutions to the initial-boundary-value problem for time-dependent flows of heat-conducting incompressible fluids through a two-dimensional channel. The boundary conditions consist of a do-nothing boundary condition on the outflow and Navier boundary conditions on the solid walls of the channel. A crucial role is played by a priori estimates in the existence analysis, however, the mixed boundary conditions under consideration do not allow us to derive an energy-type estimate of the solution. The objective is to prove the existence and uniqueness of a solution on a sufficiently short time interval for arbitrarily large data.
ZAMM-ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND MECHANIK
(2023)
Article
Mechanics
Wangxu Li, Zhenggui Li, Wei Han, Yibin Li, Shengnan Yan, Qin Zhao, Fang Chen
Summary: This study experimentally explores the relationship between the viscosity of nano-ferrofluids and temperature, magnetic-field strength, and magnetic-field inclination. The results show that the viscosity of ferrofluids decreases with increasing temperature and increases with increasing magnetic particle content. The magnetic-viscosity phenomenon is observed, where viscosity increases under the influence of a magnetic field until reaching a saturation point.
Article
Multidisciplinary Sciences
Sada Nand, Vandita Sharma, Santanu Kumar Das, Srikant Sekhar Padhee, Manoranjan Mishra
Summary: The flow through a Hele-Shaw cell is an experimental prototype for studying flow through porous media and in microfluidic devices. The effect of the gap between the plates on the flow dynamics and the formation of viscous fingering is explored. It is observed that the onset time of instability and the width of the fingers increase with an increment in the gap, while the instability increases with an increase in Peclet number. The results are validated through numerical simulations using different approaches.
SCIENTIFIC REPORTS
(2022)
Article
Instruments & Instrumentation
Shengbin Chen, Dongdong Chen, Shuli Fan, Linsheng Huo, Gangbing Song
Summary: A method using piezoceramic sensors to monitor the viscosity of fluids in dampers is proposed, with the relationship between signal amplitude and viscosity analyzed to validate its feasibility.
SMART MATERIALS AND STRUCTURES
(2021)
Article
Chemistry, Multidisciplinary
Frederik Philippi, Daniel Rauber, Kira Lieberkind Eliasen, Nathalie Bouscharain, Kristine Niss, Christopher W. M. Kay, Tom Welton
Summary: The optimization of viscosity in room temperature ionic liquids must consider both coulombic compaction and charge network interactions, as revealed by comparing the viscosity of charged and uncharged molecular mimics.
Article
Physics, Fluids & Plasmas
Patrick Ilg
Summary: In this study, a hybrid simulation scheme was proposed to accurately model the flow behavior of ferrofluids and include small-scale fluctuations. The scheme was tested in various ways and showed good agreement with theoretical predictions.
Article
Agriculture, Multidisciplinary
Monique Barreto Santos, Ianne Caroline Alves Isabel, Edwin Elard Garcia-Rojas
Summary: This study evaluated the effect of high-intensity ultrasound on depolymerization of aqueous TG solutions. The results showed that ultrasound effectively reduced the molecular weight and viscosity of TG, while increasing its solubility. Moreover, ultrasound did not alter the chemical structure of TG, only breaking down the polymer structure.
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
(2022)
Article
Chemistry, Physical
Hanqi Xu, Jinbo Wu, Yaying Hong, Weijia Wen
Summary: The study showed that the addition of Span surfactants can enhance the electrorheological response and colloidal stability of the suspension in a certain range. Below the optimal concentration of Span, the ER properties are improved by the increase of electrostatic interaction between particles. Above the limiting concentration, the formation of a double-layer surfactant structure leads to a weakening of the ER activity.
Article
Mechanics
David F. James, Abhishek Tripathi
Summary: A previous study investigated the flow of Boger fluids in a converging channel, which was also used in this work to study the behavior of viscoelastic polymer solutions. Unlike other studies where the channel abruptly narrowed, causing a secondary motion and increased pressure drop, the slowly converging channel in this study confirmed the absence of upstream vortex. Measurements showed that at high flow rates, the pressure drop increased due to the formation of an upstream secondary motion, consistent with the literature.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)
Article
Mechanics
Changhun Park, Jeong-Hyun Kim
Summary: This study investigates the bouncing dynamics of glycerol/water droplets impacting a grooved hydrophobic surface by changing the viscosity and impact speed of the droplets. It found that as the viscosity of the droplets increased, the Weber number range in which petal bouncing occurred decreased.
Article
Chemistry, Multidisciplinary
Sebastian Bruns, Christian Minnert, Laszlo Pethoe, Johann Michler, Karsten Durst
Summary: The increasing use of oxide glasses in high-tech applications demonstrates the demand for novel engineering techniques on nano- and microscale. Shaping operations of oxide glasses at room temperature usually require high temperatures close or beyond the point of glass transition T-g. However, electron irradiation has been found to facilitate the viscous flow of amorphous silica at room temperature, offering potential for local microengineering.
Article
Computer Science, Interdisciplinary Applications
Isabel Echeverribar, Sergio Martinez-Aranda, Javier Fernandez-Pato, Pilar Garcia-Navarro
Summary: Numerical simulation of unsteady viscous flow over variable topography under the influence of temperature changes is a challenge. To tackle this, the model complexity is reduced from 3D to 2D by depth averaging the equations and parallelization techniques are applied for efficient simulation. A generic model applicable to a wide range of viscous fluids and validated with synthetic cases is presented. The model is applied to a realistic lava flow case and compared to satellite observations, showing efficient results within a short simulation time.
ADVANCES IN ENGINEERING SOFTWARE
(2023)
Article
Mechanics
M. Majhi, A. K. Nayak, Subhajyoti Sahoo
Summary: This study investigates the mixing efficiency and the enhancement of electro-osmotic flow over a hydrophobic structured microchannel with a nozzle-diffuser under an external electric field. By varying the interfacial surface zeta potential, a strong convection effect is induced between two injecting fluids for different Reynolds numbers. The numerical simulation incorporates the Poisson-Nernst-Plank model to handle the thick and thin diffuse layers formed by a non-Newtonian electrolyte solution. The results showed that hydrodynamic slip increased flow velocity, while heterogeneous zeta potential generated a backflow that improved mixing efficiency. Moreover, the study discussed the mixing performance of different types of fluids and explored the effect of various physio-chemical parameters on mixing efficiency.
Article
Multidisciplinary Sciences
Tetsuro Sato, Masahiko Sato, Masaki Yamada, Hirotake Saito, Kenji Satake, Norihiro Nakamura, Kazuhisa Goto, Yosuke Miyairi, Yusuke Yokoyama
Summary: This study reveals the history of reworking movements of massive boulders and their corresponding tsunami events using the viscous remanent magnetization dating methods. The traditional radiocarbon age calculations show discrepancies, while a new method based on the stretched exponential function resolves this contradiction and provides more accurate age estimates.
SCIENTIFIC REPORTS
(2022)
Article
Mathematics, Applied
Yanjin Wang, Zhouping Xin
Summary: This study examines the dynamics of a layer of viscous incompressible fluid influenced by gravity and establishes estimates for the solution independent of viscosity and surface tension coefficients, allowing for justification of vanishing limits. In the presence of surface tension, difficulties arise from the lower regularity of temporal derivatives of mean curvature and pressure, which are mitigated by observations of crucial cancellations between curvature and pressure using dynamic boundary conditions.
SIAM JOURNAL ON MATHEMATICAL ANALYSIS
(2021)
Article
Engineering, Multidisciplinary
Yifeng Zhang, Frederic Cegla, Joseph Corcoran
Summary: Accurate temperature measurement is crucial for structural health monitoring. This study investigates non-invasive measurement of subsurface temperatures in steel components using ultrasonic techniques. Two inversion approaches are presented and evaluated for their robustness and accuracy through simulations and controlled experiments.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2021)
Article
Acoustics
Pouyan Khalili, Frederic Cegla
Summary: This article investigates the possibility of single-mode excitation of the SH1 mode at around 3 MHz . mm and its ability to detect very shallow defects. Through experiments and analytical predictions, it is shown that a signal dominated by the SH1 mode can be generated using a single PPM EMAT, allowing the detection of very shallow defects that may be missed by standard lower frequency guided wave testing.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2021)
Article
Materials Science, Characterization & Testing
Jaime Parra-Raad, Bo Lan, Frederic Cegla
Summary: This paper presents a technique for detecting crack-like defects in anisotropic materials using two orthogonal shear waves, along with a detailed study on its application. The results show the potential for this technique to become an effective tool for crack-like defect detection and material characterization.
NDT & E INTERNATIONAL
(2021)
Article
Materials Science, Characterization & Testing
Ka Yung, Arnau Garriga-Casanovas, Pouyan Khalili, Frederic Cegla
Summary: This paper presents a complete inspection system that integrates a robot mountable stereo camera system, an electromagnetic acoustic transducer (EMAT) probe, and a wireless NDE data acquisition system for contact inspections. The system can capture and merge 3D positional data of the probe and NDE data, and it has demonstrated good performance.
JOURNAL OF NONDESTRUCTIVE EVALUATION
(2022)
Article
Materials Science, Characterization & Testing
Jaime Parra-Raad, Frederic Cegla
Summary: Shear wave phased array EMATs have advantages such as not requiring direct contact with specimens and being able to operate at elevated temperatures. However, they are not commonly used due to concerns over signal excitation strength and potential changes in wavefields. This study proposes a new design to introduce shear waves into various metallic materials without compromising angle coverage or steerability.
NDT & E INTERNATIONAL
(2022)
Article
Engineering, Multidisciplinary
Yifeng Zhang, Frederic Cegla
Summary: Permanently installed ultrasonic sensors have become increasingly popular in structural health monitoring, particularly for thickness measurement and corrosion monitoring. This study proposes a dual-wave approach using co-located shear and longitudinal pulse-echo measurements to simultaneously track thickness change and temperature variation of a steel plate. The results show that this method reduces measurement uncertainties and eliminates temperature prediction drift.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2023)
Article
Energy & Fuels
Ming Huang, Niall Kirkaldy, Yan Zhao, Yatish Patel, Frederic Cegla, Bo Lan
Summary: This work presents a simple and powerful non-destructive characterization technique based on ultrasonic resonance formed by the repetitive layers within lithium-ion batteries (LIBs). By developing a physical model, the method provides important information about the inner structure of LIBs and enables quantitative tracking of internal cell properties.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Chemistry, Physical
Yifeng Zhang, Haobo Dong, Tianlei Wang, Guanjie He, Ivan P. Parkin, Frederic Cegla
Summary: This study presents a method using shear-horizontal mode guided ultrasonic waves to independently monitor the status of electrodes in a symmetric aqueous zinc-ion battery. The experimental measurements show that the velocity and attenuation of the ultrasonic wave on the opposing electrodes vary in opposite senses during cycling, and a monotonic drift can be observed with increasing cycles. The technique demonstrates sensitivity to dendrite formation, especially in the early stages of charging and discharging processes.
JOURNAL OF POWER SOURCES
(2022)
Article
Engineering, Multidisciplinary
Ming Huang, Frederic Cegla, Bo Lan
Summary: This paper presents a general stiffness matrix method for modeling waves in arbitrary multilayers. The method formulates stiffness matrices for individual layers based on wave equations and Biot theory, and assembles them into a global system of equations to obtain solutions for reflection and transmission coefficients. Its advantage lies in its computational stability and its validity has been proved through experimental validations.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2023)
Article
Engineering, Mechanical
Tong Wei, Alfredo Fantetti, Frederic Cegla, Christoph Schwingshackl
Summary: Contacting interfaces provide frictional damping in jointed structures subjected to high dynamic loads, and predicting frictional damping during vibration cycles is highly important. An optical method using transparent friction specimens and total internal reflection is developed to study the contact interface behavior during high frequency cyclic motion. The measurements show a large variation in the real area of contact during each vibration cycle, which could be linked to the kinematics of the contact interface and attributed to ageing effect and fracture of asperities.
Article
Materials Science, Multidisciplinary
Yunda Chen, Zirui Yang, Xinru Bai, Fangxin Zou, Frederic B. Cegla
Summary: In this study, an ultrasonic technique was developed to monitor the 3D morphologies of corrosion substrates in real time. It was observed that the dissolution rate of iron increased and then slowed down during the corrosion process, accompanied by the deposition of solid corrosion products and the formation of Fe3O4.
NPJ MATERIALS DEGRADATION
(2023)
Proceedings Paper
Engineering, Civil
Yifeng Zhang, Haobo Dong, Tianlei Wang, Guanjie He, Ivan P. Parkin, Frederic Cegla
Summary: This study demonstrates the sensitivity of guided ultrasonic waves to dendrite formation in batteries. By measuring the cyclical variations of wave velocity and attenuation, dendrite growth can be quantitatively tracked.
EUROPEAN WORKSHOP ON STRUCTURAL HEALTH MONITORING (EWSHM 2022), VOL 3
(2023)
Proceedings Paper
Engineering, Civil
Yifeng Zhang, Frederic Cegla
Summary: In the field of structural health monitoring, the use of ultrasonic transducers for thickness gauging and corrosion monitoring has become widespread. However, temperature fluctuations and non-uniform temperature distributions can significantly affect the accuracy of ultrasonic measurements. In this work, a dual wave approach is explored to overcome the limitations of conventional methods and accurately determine the thickness and through-thickness temperature gradient of a steel plate undergoing thickness loss at rapidly changing temperature, using co-located shear and longitudinal pulse echo measurements.
EUROPEAN WORKSHOP ON STRUCTURAL HEALTH MONITORING (EWSHM 2022), VOL 3
(2023)
Article
Engineering, Biomedical
Thomas A. G. Hall, Frederic Cegla, Richard J. van Arkel
Summary: This research proposes an embedded ultrasound system to monitor implant fixation and temperature, providing early warning and avoiding the need for batteries and microprocessors. The simple design with only two components allows for simultaneous measurement of fixation and temperature.
IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS
(2021)
