scholarly journals High-speed ultrasound imaging in dense suspensions reveals impact-activated solidification due to dynamic shear jamming

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Endao Han ◽  
Ivo R. Peters ◽  
Heinrich M. Jaeger
Keyword(s):  
Ultrasound Imaging ◽  
High Speed ◽  
Dynamic Shear ◽  
Dense Suspensions ◽  
Shear Jamming

scholarly journals Direct observation of dynamic shear jamming in dense suspensions

Nature ◽  
2016 ◽  
Vol 532 (7598) ◽  
pp. 214-217 ◽  
Author(s):  
Ivo R. Peters ◽  
Sayantan Majumdar ◽  
Heinrich M. Jaeger
Keyword(s):  
Direct Observation ◽  
Dynamic Shear ◽  
Dense Suspensions ◽  
Shear Jamming

High-speed ultrasound imaging of laser-induced cavitation bubbles

2021 ◽  
Vol 119 (11) ◽  
pp. 114101
Author(s):  
S. Izak Ghasemian ◽  
F. Reuter ◽  
C. D. Ohl
Keyword(s):  
Ultrasound Imaging ◽  
High Speed ◽  
Cavitation Bubbles

scholarly journals Controlling shear jamming in dense suspensions via the particle aspect ratio

Soft Matter ◽  
2019 ◽  
Vol 15 (18) ◽  
pp. 3649-3654 ◽  
Author(s):  
Nicole M. James ◽  
Huayue Xue ◽  
Medha Goyal ◽  
Heinrich M. Jaeger
Keyword(s):  
Aspect Ratio ◽  
Shear Thickening ◽  
Dense Suspensions ◽  
Shear Jamming ◽  
Particle Aspect Ratio

Dense suspensions of particles in a liquid exhibit rich, non-Newtonian behaviors such as shear thickening (ST) and shear jamming (SJ).

scholarly journals A dinoflagellate exploits toxins to immobilize prey prior to ingestion

2010 ◽  
Vol 107 (5) ◽  
pp. 2082-2087 ◽  
Author(s):  
Jian Sheng ◽  
Edwin Malkiel ◽  
Joseph Katz ◽  
Jason E. Adolf ◽  
Allen R. Place
Keyword(s):  
High Speed ◽  
Algal Bloom ◽  
Harmful Algal Bloom ◽  
Fish Kills ◽  
Karlodinium Veneficum ◽  
Prey Behavior ◽  
Dense Suspensions ◽  
Holographic Microscopy ◽  
Critical Understanding ◽  
Grazing Pressures

Toxins produced by the harmful algal bloom (HAB) forming, mixotrophic dinoflagellate Karlodinium veneficum have long been associated with fish kills. To date, the perceived ecological role for toxins has been relief from grazing pressures. Here, we demonstrate that karlotoxins also serve as a predation instrument. Using high-speed holographic microscopy, we measure the swimming behavior of several toxic and nontoxic strains of K. veneficum and their prey, Storeatula major, within dense suspensions. The selected strains produce toxins with varying potency and dosages, including a nontoxic one. Results clearly show that mixing the prey with the predatory, toxic strains causes prey immobilization at rates that are consistent with the karlotoxins’ potency and dosage. Even prey cells that continue swimming slow down after exposure to toxic predators. The swimming characteristics of predators vary substantially in pure suspensions, as quantified by their velocity, radii of helical trajectories, and direction of helical rotation. When mixed with prey, all toxic strains that are involved in predation slow down. Furthermore, they substantially reduced their predominantly vertical migration, presumably to remain in the vicinity of their prey. Conversely, the nontoxic control strain does not alter its swimming and does not affect prey behavior. In separate experiments, we show that exposing prey to exogenous toxins also causes prey immobilization at rates consistent with potency. Clearly, the toxic predatory strains use karlotoxins as a means of stunning their prey, before ingesting it. These findings add a substantiated critical understanding for why some HAB species produce such complex toxin molecules.

scholarly journals Shear jamming and fragility in dense suspensions

2019 ◽  
Vol 21 (3) ◽  
Author(s):  
Ryohei Seto ◽  
Abhinendra Singh ◽  
Bulbul Chakraborty ◽  
Morton M. Denn ◽  
Jeffrey F. Morris
Keyword(s):  
Dense Suspensions ◽  
Shear Jamming

scholarly journals Dynamic shear jamming in dense granular suspensions under extension

2017 ◽  
Vol 95 (1) ◽  
Author(s):  
Sayantan Majumdar ◽  
Ivo R. Peters ◽  
Endao Han ◽  
Heinrich M. Jaeger
Keyword(s):  
Dynamic Shear ◽  
Granular Suspensions ◽  
Shear Jamming

scholarly journals Orientational arrest in dense suspensions of elliptical particles under oscillatory shear flows

2021 ◽  
Author(s):  
Zakiyeh Yousefian ◽  
Martin Trulsson
Keyword(s):  
Aspect Ratio ◽  
Shear Flows ◽  
Oscillatory Shear ◽  
Large Strains ◽  
Nematic Order ◽  
Rheological Response ◽  
Lower Viscosity ◽  
Dense Suspensions ◽  
Elliptical Particles ◽  
Shear Jamming

Abstract We study the rheological response of dense suspensions of elliptical particles, with an aspect ratio equal to 3, under oscillatory shear flows and imposed pressure by numerical simulations. Like for the isotropic particles, we find that the oscillatory shear flows respect the Cox-Merz rule at large oscillatory strains but differ at low strains, with a lower viscosity than the steady shear and higher shear jamming packing fractions. However, unlike the isotropic cases (i.e., discs and spheres), frictionless ellipses get dynamically arrested in their initial orientational configuration at small oscillatory strains. We illustrate this by starting at two different configurations with different nematic order parameters and the average orientation of the particles. Surprisingly, the overall orientation in the frictionless case is uncoupled to the rheological response close to jamming, and the rheology is only controlled by the average number of contacts and the oscillatory strain. Having larger oscillatory strains or adding friction does, however, help the system escape these orientational arrested states, which are evolving to a disordered state independent of the initial configuration at low strains and ordered ones at large strains.

Controlled Contact Cutting Tools

1959 ◽  
Vol 81 (2) ◽  
pp. 139-147 ◽  
Author(s):  
B. T. Chao ◽  
K. J. Trigger
Keyword(s):  
Shear Stress ◽  
Surface Finish ◽  
High Speed ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Substantial Reduction ◽  
Cutting Fluids ◽  
Dynamic Shear ◽  
Effective Utilization ◽  
High Speed Cutting

A substantial reduction in power consumption, an increase in tool life, more effective utilization of cutting fluids, and improved surface finish on the machined workpiece have been achieved by suitably controlling the length of tool-chip contact. Reasons for these findings are discussed in terms of basic variables in chip formation mechanics. Artificially restricted contact tools open new avenues for metal cutting research. Machining data obtained with such tools provide further evidence of the invariant behavior of the dynamic shear stress of metals under high-speed cutting conditions, and unfold interesting information on the intricate nature of tool-chip contact.

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