Article
Polymer Science
N'dri Arthur Konan, Eilis Rosenbaum, Mehrdad Massoudi
Summary: In this study, the boundary-layer flow of a Herschel-Bulkley fluid due to a moving plate is investigated. Computational fluid dynamics and regularization methods are used to solve the governing equations numerically. The results show good agreement between simulations and experimental data, with accurate prediction of boundary layer thicknesses and strong sensitivities to the rheological properties of the fluid.
Article
Mechanics
Rodrigo S. Mitishita, Jordan A. MacKenzie, Gwynn J. Elfring, Ian A. Frigaard
Summary: Research on turbulent flows of high Reynolds number viscoplastic fluids has been conducted, and an experimental study was carried out to investigate the effect of different concentrations of Carbopol on the rheology and turbulence statistics of the fluid.To increase Reynolds number with a Carbopol solution, streamwise Reynolds stresses approach Newtonian values in the core, suggesting diminishing effects of shear-thinning. The addition of Carbopol enhances turbulence anisotropy and alters energy content at different scales in comparison to water.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2021)
Article
Mechanics
A. Pourzahedi, M. Zare, I. A. Frigaard
Summary: Bubbles rising steadily in Carbopol often have an inverted teardrop shape with a pointed tail, which may be caused by viscoelasticity or fluid memory effects. Even after eliminating all possibilities of memory effects, the pointed tail still exists in steady bubble propagation. This suggests that the tail shape results from a combination of rheology and steady fluid deformation around the rising bubble.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2021)
Article
Mechanics
Eliane Younes, Michal Himl, Zdenek Stary, Teodor Burghelea
Summary: This study presents an in-situ visualization of the microstructure of a Carbopol gel flowing in a micro-channel using a novel chemical protocol to stain solid material units. By accurately identifying the solid/fluid material units advected by confined microscopic flow, the study reports a full statistical description of their distributions in terms of space and time averages, probability density functions, and space-time correlations for the first time.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2021)
Article
Mechanics
H. Koochi, Jonatan Mac Intyre, M. Korhonen, A. Puisto, N. Maleki-Jirsaraei, M. J. Alava
Summary: The impact of thixotropy on the settling behavior of a solid sphere is studied using a finite element-computational fluid dynamics simulation. The flow behavior is evaluated by coupling the Navier-Stokes equations with the dynamic evolution of an initially heterogeneous fluid's microstructure. The study identifies different settling regimes based on the degree of structuring, associated heterogeneity, local morphology of the microstructure, and stress induced by the sphere. The results show that the competition between orthokinetic and perikinetic build-up and shear-induced break-down of the microstructure plays a vital role in understanding the connection between flow curve and settling behavior of the fluids.
Article
Chemistry, Physical
Raffaele Graziano, Valentina Preziosi, Dario Uva, Giovanna Tomaiuolo, Behzad Mohebbi, Jan Claussen, Stefano Guido
Summary: This study observed the microstructure of neutralized polyacrylic acid (Carbopol) in water using confocal microscopy under both static and flow conditions. It found that under static conditions, a suspension is formed with swollen particles dispersed in a water-rich continuous phase, while under flow conditions, there is a particle-concentrated plug core. By separating the dispersed and continuous phase, evidence of a miscibility gap in the phase behavior of Carbopol in water was provided.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Nicola Antonio Di Spirito, Shadi Mirzaagha, Ernesto Di Maio, Nino Grizzuti, Rossana Pasquino
Summary: This study investigates the dynamics of bubble rupture and hole opening in a non-Newtonian fluid by analyzing the retraction process of thin films after inflation. A new mathematical model is proposed to understand the opening velocity, taking into account various forces such as viscous, elastic, surface, and inertial forces. Experimental results show good agreement between the predicted opening velocity using the proposed model and the actual measurements.
Review
Construction & Building Technology
Dengwu Jiao, Robin De Schryver, Caijun Shi, Geert De Schutter
Summary: Thixotropic structural build-up is an intrinsic property of fresh cementitious materials, which plays a significant role in the pumpability, stability, and formwork filling of concrete. Evaluation of the evolution of static yield stress and storage modulus can be used to assess the structural build-up of fresh cementitious materials. Increasing particle volume fraction, decreasing surface coverage, and reducing maximum packing fraction have a positive effect on the increase in structural build-up.
CEMENT & CONCRETE COMPOSITES
(2021)
Article
Energy & Fuels
Jijiang Ge, Qianhui Wu, Lei Ding, Hongbin Guo, An Zhao
Summary: The THSG gel system shows superior rheological properties and dilution compared to traditional gel systems, making it more effective in injecting and filling gelant into fractures and small apertures. The clay particles strengthened THSG gels have high storage modulus and rupture pressure, effectively preventing the adverse effects of gravity segregation.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Construction & Building Technology
Xuping Ji, Tinghong Pan, Xingyao Liu, Wenhao Zhao, Linpu Du, Jianzhong Liu, Fangyu Han, Jianfang Sha
Summary: This paper compares four widely used test procedures in order to determine their relationships. The results indicate that test procedures based on the break-down process are difficult to accurately evaluate the thixotropy of mixtures. The short-term structural build-up rate is more suitable for characterizing thixotropic properties.
STRUCTURAL CONCRETE
(2023)
Article
Mechanics
Yixuan Hou, Zhao Jin, Xinzhe Que, Dongdong Yuan, Yonggang Lin, Mingquan Yu, Yongchao Zhou, Yiping Zhang
Summary: In this study, the thixotropic yielding behaviors of MLPS with concentrations of 3, 4, 5, and 6 wt% were investigated using rheological testing methods. The static and dynamic yield stresses measured by different methods were analyzed and compared. The flow curves of shear rate ramp tests were found to be inapplicable due to shear banding, while the yield stresses obtained by shear stress ramp and oscillatory shear tests showed consistency. A thixotropic visco-plastic model incorporating static and dynamic yield stress was established to describe the thixotropic yielding behavior of MLPS suspension.
Article
Physics, Multidisciplinary
Joel T. Clemmer, Ishan Srivastava, Gary S. Grest, Jeremy B. Lechman
Summary: This study uses discrete element simulations to explore a wide range of flow types in granular systems under large strains, characterizing invariants of the stress tensor for different inertial numbers and interparticle friction coefficients. The research identifies a strong dependence on the type of flow, which increases with higher inertial numbers or friction coefficients. Standard yield models are compared with data to describe the stress dependence on flow type in steady-state flow and at finite rates.
PHYSICAL REVIEW LETTERS
(2021)
Article
Biotechnology & Applied Microbiology
Mohammad Ahmad, Ruchi Pathania, Abantika Chowdhury, Jai Kumar Gupta, Chandra Dev, Shireesh Srivastava
Summary: The study demonstrates that adaptation of Saccharomyces cerevisiae to high salt concentrations significantly improves fermentation performance at high sugar concentrations, leading to higher ethanol yields and reduced lag phase.
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
(2021)
Article
Nanoscience & Nanotechnology
Siqi Chen, Yongjie Dong, Song Ma, Jiayuan Ren, Xipeng Yang, Yingjie Wang, Shaoyu Lu
Summary: Development of a superstretching MXene composite hydrogel sensor capable of real-time detection of human motion signals, achieving high sensitivity and rapid resilience for discerning multidirectional human motions.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Mechanics
Esteban F. Medina-Banuelos, Benjamin M. Marin-Santibanez, Emad Chaparian, Crystal E. Owens, Gareth H. McKinley, Jose Perez-Gonzalez
Summary: It has been discovered that the steady fractal vane-in-cup (fVIC) flow of complex fluids using vanes with fractal cross sections can produce an almost axisymmetric flow field and rotation rate-independent effective radius, making it a reliable measurement tool for complex fluids. However, axial shearing/compression during the insertion of the rheometric tool in the sample also accelerates syneresis, leading to shear banding for Couette and fVIC flows.
JOURNAL OF RHEOLOGY
(2023)