Complex Biological Fluid Flow Through Microfabricated Polysilicon Microneedles

2000 ◽  
Author(s):  
Jeffrey D. Zahn ◽  
Dorian Liepmann
Keyword(s):  
Fluid Flow ◽  
Biological Fluid ◽  
Biological Fluids ◽  
Sample Extraction ◽  
Flow Through ◽  
Complex Features ◽  
Small Channels ◽  
Biological Solutions ◽  
Phosphate Buffered Saline ◽  
Fahraeus Effect

Abstract Microneedles can be used for sample extraction or injection for biomedical applications. It is important to understand how complex biological fluids behave within the needles because non-newtonian effects are associated with fluid flow of concentrated biological solutions. Different concentrations of sheep blood diluted with phosphate buffered saline (PBS) were investigated in different planar needle geometries. Only slight shear thinning behavior was observed, and only slight changes in apparent viscosity were recorded even at higher hematocrit levels. This is hypothesized to be a result of the Fahraeus effect in which cells are excluded from the wall regions in small channels. Microneedles with complex features clogged easily whereas needles with larger hydraulic radii allowed higher concentrations of blood to flow through them. However, at higher hematocrit levels (>25%) even the lower resistance needle clogged. Further investigations are needed to correlate how geometry affects flow of complex cellular suspensions.

A Model to Guide Template-Based Nanoparticle Printing Development

2015 ◽  
Author(s):  
David A. Rolfe ◽  
Kristen L. Dorsey ◽  
Jim C. Cheng ◽  
Albert P. Pisano
Keyword(s):  
Fluid Flow ◽  
Development Stage ◽  
High Fidelity ◽  
Sorption Rate ◽  
Element Analysis ◽  
Fluid Velocities ◽  
Flow Through ◽  
Complex Features ◽  
Dry Out ◽  
Nanoparticle Ink

Advective molding in vapor-permeable templates is an evaporation-driven process for submicron molding of nanoparticles with high fidelity. In this process, nanoparticle ink is drawn through channels in a vapor permeable template. The ink solvent is sorbed into the channel walls and evaporated through the template. As the complexity (e.g., width variation and turns in a channel) of the desired features increases, so does the likelihood of incompletely patterned nanoparticles. Patterning difficulties arise from dry-out, a condition where the nanoparticle ink dries before reaching the end of the channel and blocks the flow of more ink. Predicting dry-out during the template development stage is a critical step in patterning complex features. In this work, we present a method for predicting dry-out by incorporating two layers of finite element analysis. First, models for ink fluid flow and solvent diffusion through the template are used to determine wall sorption rate correlations. Fluid flow through complex templates is then modeled in a fluid-only model, with the flux rate into the template walls determined by the sorption rate correlations. The fluid velocities and wall sorption rates are then used to determine the likelihood of dry-out. The linked simulations successfully predict points of improper nanoparticle patterning in real templates.

STABILITY OF COUPLE STRESS FLUID FLOW THROUGH A HORIZONTAL POROUS LAYER

2016 ◽  
Vol 19 (5) ◽  
pp. 391-404 ◽  
Author(s):  
B. M. Shankar ◽  
I. S. Shivakumara ◽  
Chiu-On Ng
Keyword(s):  
Fluid Flow ◽  
Porous Layer ◽  
Couple Stress ◽  
Couple Stress Fluid ◽  
Flow Through

3D NUMERICAL INVESTIGATION OF FLUID FLOW THROUGH OPEN-CELL METAL FOAMS USING MICRO-TOMOGRAPHY IMAGES

2014 ◽  
Vol 17 (11) ◽  
pp. 1019-1029 ◽  
Author(s):  
Mohammad Zafari ◽  
Masoud Panjepour ◽  
Mohsen Davazdah Emami ◽  
Mahmood Meratian
Keyword(s):  
Fluid Flow ◽  
Numerical Investigation ◽  
Metal Foams ◽  
Open Cell ◽  
Flow Through ◽  
Micro Tomography

A Non-Newtonian Fluid Flow Model for the Slip Condition on Blood Flow through a Stenosed Artery using Power-law Fluid

2018 ◽  
Vol 9 (7) ◽  
pp. 871-879
Author(s):  
Rajesh Shrivastava ◽  
R. S. Chandel ◽  
Ajay Kumar ◽  
Keerty Shrivastava and Sanjeet Kumar
Keyword(s):  
Blood Flow ◽  
Fluid Flow ◽  
Newtonian Fluid ◽  
Power Law ◽  
Flow Model ◽  
Slip Condition ◽  
Power Law Fluid ◽  
Stenosed Artery ◽  
Flow Through
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