Cross-stream migration and coalescence of droplets in a microchannel co-flow using magnetophoresis

2019 ◽  
Vol 31 (11) ◽  
pp. 112003 ◽  
Author(s):  
U. Banerjee ◽  
C. Mandal ◽  
S. K. Jain ◽  
A. K. Sen
Keyword(s):  
Stream Migration

Haemorheological Effects on Thrombocyte Adhesion and Aggregation Found Under Controlled Flow Conditions

1979 ◽  
Author(s):  
P.D. Richardson
Keyword(s):  
Rate Of Change ◽  
Continuous Observation ◽  
Flow Conditions ◽  
Wide Range ◽  
Stream Migration ◽  
Local Shear ◽  
Videotape Recording ◽  
Controlled Flow ◽  
A Site

Thrombocyte adhesion and aggregation in a vessel or on a chamber wall can be measured most readily if the flow is controlled and steady, and continuous observation is used. Videotape recording is very helpful for subsequent quantification of the dynamics. The adhesion of each thrombocyte can occur for a finite time interval:this interval has been observed to have a wide range. Platelets which escape often leave open a site which attracts other platelets preferentially. The rate of change of adhesion density (platelets/mm2) is affected by the local shear rate and the shear history upstream. Aggregation is affected similarly, and also proceeds with some platelet turnover. The role of erythrocytes in facilitating cross-stream migration of thrombocytes (which can enhance the growth rate of large thrombi) appears due in part to convective flow fields induced by the motion of erythrocytes in a shear flow, which can be demonstrated theoretically and experimentally. Observations of the phenomenlogy of adhesion and aggregation under controlled flow conditions and comparison with fLu id-dynamically based theory allows representation in terras of a small number of parameters with prospects of prediction of behaviour over a wide range of haemodynamic conditions; biochemical changes lead to changes in values of the parameters, so that activating agents and inhibiting agents modify values in different directions.

scholarly journals Upstream rheotaxis of catalytic Janus spheres

2021 ◽  
Author(s):  
Priyanka Sharan ◽  
Zuyao Xiao ◽  
Viviana Mancuso ◽  
William E. Uspal ◽  
Juliane Simmchen
Keyword(s):  
Fluid Flow ◽  
Type System ◽  
Shear Plane ◽  
High Flow ◽  
Physical Factors ◽  
Theoretical Studies ◽  
Directional Response ◽  
Swimming Pattern ◽  
Flow Speeds ◽  
Stream Migration

Fluid flow is ubiquitous in many environments that form habitats for microorganisms. The tendency of organisms to navigate towards or away from flow is termed rheotaxis. Therefore, it is not surprising that both biological and artificial microswimmers show responses to flows that are determined by the interplay of chemical and physical factors. In particular, to deepen understanding of how different systems respond to flows, it is crucial to comprehend the influence played by swimming pattern. In recent studies, pusher-type Janus particles exhibited cross-stream migration in externally applied flows. Earlier, theoretical studies predicted a positive rheotactic response for puller-type spherical Janus micromotors. To compare to a different swimmer, we introduce Cu@SiO2 micromotors that swim towards their catalytic cap. Based on experimental observations, and supported by flow field calculations using a model for self-electrophoresis, we hypothesize that they behave effectively as a puller-type system. We investigate the effect of externally imposed flow on these spherically symmetrical Cu@SiO2 active Janus colloids, and we indeedobserve a steady upstream directional response. Through a simple squirmer model for a puller, we recover the major experimental observations. Additionally, the model predicts a unique “jumping” behaviour for puller-type micro- motors at high flow speeds. Performing additional experiments at high flow speeds, we capture this phenomenon, in which the particles “roll” with their swimming axes aligned to the shear plane, in addition to being dragged down- stream by the fluid flow.

Role of Functionality in Cross-Stream Migration, Structures, and Dynamics of Star Polymers in Poiseuille Flow

2020 ◽  
Vol 53 (22) ◽  
pp. 9993-10004
Author(s):  
Aiqing Liu ◽  
Zhenyue Yang ◽  
Lijun Liu ◽  
Jizhong Chen ◽  
Lijia An
Keyword(s):  
Poiseuille Flow ◽  
Star Polymers ◽  
Stream Migration

Development of an in-stream migration model for Gammarus pulex L. (Crustacea, Amphipoda) as a tool in river restoration management

2005 ◽  
Vol 40 (2) ◽  
pp. 249-261 ◽  
Author(s):  
Andy P. Dedecker ◽  
Peter L. M. Goethals ◽  
Tom D’heygere ◽  
Niels De Pauw
Keyword(s):  
River Restoration ◽  
Gammarus Pulex ◽  
Migration Model ◽  
Restoration Management ◽  
Stream Migration
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