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Cavities fabricated on the microscale have a wide variety of applications, from microwells for cell cultures, microfluidic channels for drug delivery systems to waveguide structures for RF applications. Micro-cavities are particularly useful for sensing applications, such as cavity-based pressure sensors and gap-based capacitive sensors. Cavity structures have been widely demonstrated in MEMS devices using typical semiconductor processing. However, the development of similar structures for flexible applications poses additional challenges. While flexible cavity structures have been fabricated in laboratory environments, challenges arise when these structures are integrated into a larger flexible sensing device or flexible hybrid electronics system. An additive manufacturing approach to cavity formation is presented which utilizes a 3D screen-printing process and in-situ cure. Patterned micro-structures are formed by building up layers of dielectric ink interspersed as needed with printed conductive traces. A proof-of-concept microfluidic channel-based capacitor is fabricated to demonstrate the potential sensing applications for the fabricated microcavities.
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Water entry of spheres with impact-axis channels
Spheres are the most studied water entry projectile due to their symmetry and simplicity, but in practical applications, it is rare that an impacting body is perfectly spherical. Perturbations to the classical impactor are thus critical for aligning fundamental investigation with more advanced engineering applications. This study investigates the water entry of hydrophilic and hydrophobic spheres with through-channels along the water entry axis and producing deep seal cavities. The channels allow water to pass through the sphere to create a jet tailing the sphere and hastening cavity pinch-off. Channeled spheres produce smaller cavities than their intact counterparts and suppress the onset of cavity formation. Spheres with channels show similar drag coefficients as solid, intact spheres.
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- Award ID(s):
- 2153740
- PAR ID:
- 10479462
- Publisher / Repository:
- Physics of Fluids
- Date Published:
- Journal Name:
- Physics of Fluids
- Volume:
- 35
- Issue:
- 12
- ISSN:
- 1070-6631
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0175406
