RHEOLOGICAL EXPERIMENTS OF A DUAL-WAX MEDIUM FOR ANALOG MODELING OF FAULT ASPERITY KINEMATICS

In order to improve sewage sludge characterization for both dewatering and agricultural spreading, we have studied their electrical and rheological properties. On the one hand, electrical measurements give a picture of the microstructure of the material (charges, particles mobility), whereas on the other hand, rheological experiments describe its macrostructure (consistency). The interactions of the matter are the link between them. Our results showed that sludge becomes more conductive when its dry content (for a defined composition) or the temperature increases, and also during aging. In parallel its apparent viscosity increases with the dry content but decreases with the temperature or during aging. In each case a clear correlation was found between electrical and rheological parameters. This relationship clearly depends on sludge composition, and also on parameters such as the temperature, the observation frequency, the velocity range in the case of relaxation experiments. Finally, those types of experiments can be correlated to improve the comprehension of sludge structure and consistency characterization.

Download Full-text

Rheology of rounded mammalian cells over continuous high-frequencies

Nature Communications ◽

10.1038/s41467-021-23158-0 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Gotthold Fläschner ◽

Cosmin I. Roman ◽

Nico Strohmeyer ◽

David Martinez-Martin ◽

Daniel J. Müller

Keyword(s):

High Frequency ◽

Mammalian Cells ◽

Mechanical Response ◽

Cell Mass ◽

Low Frequency ◽

Mass Measurements ◽

High Frequencies ◽

Polymer Relaxation ◽

Continuous Frequency ◽

Rheological Experiments

AbstractUnderstanding the viscoelastic properties of living cells and their relation to cell state and morphology remains challenging. Low-frequency mechanical perturbations have contributed considerably to the understanding, yet higher frequencies promise to elucidate the link between cellular and molecular properties, such as polymer relaxation and monomer reaction kinetics. Here, we introduce an assay, that uses an actuated microcantilever to confine a single, rounded cell on a second microcantilever, which measures the cell mechanical response across a continuous frequency range ≈ 1–40 kHz. Cell mass measurements and optical microscopy are co-implemented. The fast, high-frequency measurements are applied to rheologically monitor cellular stiffening. We find that the rheology of rounded HeLa cells obeys a cytoskeleton-dependent power-law, similar to spread cells. Cell size and viscoelasticity are uncorrelated, which contrasts an assumption based on the Laplace law. Together with the presented theory of mechanical de-embedding, our assay is generally applicable to other rheological experiments.

Download Full-text

High temperature and pressure rheological experiments on felsic granulite

10.1002/essoar.10504281.1 ◽

2020 ◽

Author(s):

Dapeng Wen ◽

Yongfeng Wang ◽

Junfeng Zhang ◽

Pengxiao Li ◽

Zhen-Min Jin

Keyword(s):

High Temperature ◽

High Temperature And Pressure ◽

Temperature And Pressure ◽

Rheological Experiments

Download Full-text

Modeling of Shear Rheological Behavior of Uncured Rubber Melt

Applied Rheology ◽

10.1515/arh-2020-0111 ◽

2020 ◽

Vol 30 (1) ◽

pp. 130-137

Author(s):

Hengxiao Yang ◽

Qimian Mo ◽

Hengyu Lu ◽

Shixun Zhang ◽

Wei Cao ◽

...

Keyword(s):

Shear Rate ◽

Constitutive Model ◽

Incompressible Fluid ◽

Rheological Behavior ◽

Rheological Characteristics ◽

One Dimensional ◽

Ptt Model ◽

Rate Region ◽

Proposed Model ◽

Rheological Experiments

AbstractTo describe uncured rubber melt flow, a modified Phan–Thien–Tanner (PTT) model was proposed to characterize the rheological behavior and a viscoelastic one-dimensional flow theory was established in terms of incompressible fluid. The corresponding numerical method was constructed to determine the solution. Rotational rheological experiments were conducted to validate the proposed model. The influence of the parameters in the constitutive model was investigated by comparing the calculated and experimental viscosity to determine the most suitable parameters. The uncured rubber viscosity was 3–4 orders larger than that of plastic and did not have a visible Newtonian region. Compared with the Cross-Williams-Landel-Ferry (Cross-WLF) and original PTT models, the modified PTT model can describe the rheological characteristics in the entire shear-rate region if the parameters are set correctly.

Download Full-text

Influence of preexisting salt diapirs during thrust wedge evolution and secondary welding: Insights from analog modeling

Journal of Structural Geology ◽

10.1016/j.jsg.2021.104374 ◽

2021 ◽

pp. 104374

Author(s):

P. Santolaria ◽

O. Ferrer ◽

M.G. Rowan ◽

M. Snidero ◽

N. Carrera ◽

...

Keyword(s):

Analog Modeling

Download Full-text

Physical analog modeling of pull-apart basin evolution

Tectonophysics ◽

10.1016/s0040-1951(97)00193-5 ◽

1998 ◽

Vol 285 (1-2) ◽

pp. 21-40 ◽

Cited By ~ 85

Author(s):

Bret Rahe ◽

David A. Ferrill ◽

Alan P. Morris

Keyword(s):

Basin Evolution ◽

Pull Apart Basin ◽

Analog Modeling

Download Full-text

Vanadium Pentoxide Gels: Structural Development and Rheological Properties

MRS Proceedings ◽

10.1557/proc-180-759 ◽

1990 ◽

Vol 180 ◽

Cited By ~ 5

Author(s):

J.K. Bailey ◽

T. Nagase ◽

G.A. Pozarnsky ◽

M.L. Mecartney

Keyword(s):

Vanadium Pentoxide ◽

Structural Development ◽

Small Particles ◽

Rheological Characterization ◽

Cryogenic Transmission Electron Microscopy ◽

Transmission Electron ◽

Before And After ◽

Constant Shear Stress ◽

Steady Shearing ◽

Rheological Experiments

ABSTRACTCryogenic transmission electron Microscopy (cryo-TEM) and rheological characterization were conducted in order to understand structural development of vanadium pentoxide gels during processing. Sols were prepared by ion exchange from sodium metavanadate solutions. Cryo-TEM revealed that fine threads about 1.5nm wide initially form and grow into ribbons approximately 25nm wide and at least 1000nm long. The threads appear to self assemble into the ribbons. During this structural development, the dynamic viscosity increased. Upon steady shearing of the sols, the system exhibited thixotropy, i.e. the viscosity decreased with time under constant shear stress and subsequently rheopexy, the viscosity increased with time. Comparison of the structure before and after shearing indicated that during the rheological experiments aggregation of small particles or fragments was occurring.

Download Full-text