Numerical analysis of air bubble formation in PDMS micro-channels in negative pressure-driven flow

2015 ◽  
Author(s):  
Jixiao Liu ◽  
Songjing Li
Keyword(s):  
Numerical Analysis ◽  
Negative Pressure ◽  
Bubble Formation ◽  
Air Bubble ◽  
Micro Channels ◽  
Pressure Driven Flow ◽  
Pressure Driven

Analytical study of mixed electroosmotic-pressure-driven flow in rectangular micro-channels

2012 ◽  
Vol 27 (5) ◽  
pp. 599-616 ◽  
Author(s):  
Saeid Movahed ◽  
Reza Kamali ◽  
Mohammad Eghtesad ◽  
Amir Khosravifard
Keyword(s):  
Analytical Study ◽  
Micro Channels ◽  
Pressure Driven Flow ◽  
Pressure Driven

Thermal Analysis of Mixed Electroosmotic and Pressure Driven Flows in Two-Dimensional Straight Microchannels

Volume 4 ◽  
2004 ◽  
Author(s):  
Keisuke Horiuchi ◽  
Prashanta Dutta
Keyword(s):  
Heat Transfer ◽  
Thermal Analysis ◽  
Pressure Gradient ◽  
Two Dimensional ◽  
Transfer Coefficients ◽  
Nusselt Numbers ◽  
Micro Channels ◽  
Micro Flows ◽  
Pressure Driven Flow ◽  
Pressure Driven

Analytical solution for the temperature distributions, heat transfer coefficients, and Nusselt numbers of steady electroosmotic flows with an arbitrary pressure gradient are obtained for two-dimensional straight micro-channels. The thermal analysis considers interaction among inertial, diffusive and Joule heating terms in order to obtain the thermally developing behavior of mixed electroosmotic and pressure driven flows. In mixed flow cases, the governing equation for energy is not separable in general. Therefore, we introduced a new method that considers the extended Graetz problem. Heat transfer characteristics are presented for low Reynolds number micro-flows where the viscous and electric field terms are very dominant. Analytical results show that the heat transfer coefficient of mixed-electroosmotic and pressure driven flow is smaller than that of pure electroosmotic flow. For the parameter range studied here (Re<0.7), the fully developed Nusselt number is independent of the thermal Peclet number and pressure gradient. Moreover, in mixed electroosmotic and pressure driven flows, the thermal entrance length increases with the imposed pressure gradient.

A comparison of 2 cementing techniques in hip resurfacing using human femoral heads

2021 ◽  
pp. 112070002199706
Author(s):  
Sarah J Shiels ◽  
Martin Williams ◽  
Gordon C Bannister ◽  
Richard P Baker
Keyword(s):  
Femoral Head ◽  
Femoral Component ◽  
Bubble Formation ◽  
Young Male ◽  
Cement Mantle ◽  
Hip Resurfacing ◽  
Air Bubble ◽  
Low Viscosity ◽  
Femoral Heads ◽  
Group 2

Introduction: Hip resurfacing remains a valid option in young male patients. The creation of the optimum cement mantle aids fixation of the femoral component. If the cement mantle is too thick the prosthesis can remain proud leading to early failure or if it penetrates too far into the femoral head, it may cause osteonecrosis. Method: 18 of 96 femoral heads collected from patients undergoing total hip arthroplasty were matched for their surface porosity. They were randomly allocated into 2 different cementing groups. Group 1 had the traditional bolus of cement technique, while group 2 had a modified cementing technique (swirl) where the inside of the femoral component was lined with an even layer of low viscosity cement. Results: The traditional bolus technique had significantly greater cement mantle thickness in 3 of 4 zones of penetration ( p = 0.002), greater and larger air bubble formation (6 of 9 in bolus technique vs. 1 in 9 in swirl technique, p = 0.05) and more incomplete cement mantles compared with the swirl technique. There was no relationship to femoral head porosity. Conclusion: The swirl technique should be used to cement the femoral component in hip resurfacing. Long-term clinical studies would conform if this translates into increased survivorship of the femoral component.

scholarly journals Molecular dynamics study of pressure-driven water transport through graphene bilayers

2016 ◽  
Vol 18 (3) ◽  
pp. 1886-1896 ◽  
Author(s):  
Bo Liu ◽  
Renbing Wu ◽  
Julia A. Baimova ◽  
Hong Wu ◽  
Adrian Wing-Keung Law ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
High Pressure ◽  
Water Transport ◽  
Layered Structures ◽  
Water Molecules ◽  
Flow Rates ◽  
Ultra High Pressure ◽  
Pressure Driven Flow ◽  
Pressure Driven

Water molecules form layered structures inside graphene bilayers and ultra-high pressure-driven flow rates can be observed.

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