Dr. Charles A. Rohde Profile

Dr. Charles A. Rohde

at US Naval Research Lab

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Publications (6)

Proceedings Article | 8 March 2021 Presentation + Paper

Benchmarking print quality of additively manufactured ceramic nanosuspensions toward consistent fabrication using laser stereolithography

Celeste Brown, Nicholas Charipar, Charles Rohde, Grant Warner, Alberto Piqué

Proceedings Volume 11677, 116770W (2021) https://doi.org/10.1117/12.2583124

KEYWORDS: Additive manufacturing, Stereolithography, Ceramics, Nanolithography, Nonimpact printing, Composites, Nanoparticles, Surface roughness, Silica, Metamaterials

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Architected materials present an opportunity to overcome the limited ability of brittle piezoelectric ceramics to strain under electromechanical load. In the absence of a commercially available resin containing piezoelectric nanoparticles, this work seeks to investigate the printability and thermal processability of a prepared piezoelectric particle loaded slurry using laser stereolithography. This was accomplished by comparing the cure depth, in-plane resolution, and the dimensional accuracy achieved with a piezoelectric slurry prepared with barium titanate, to a commercially available silica and alumina-based suspension. The study of thermal processability revealed the dimensional sensitivity of fabricated open architectures to sintering temperature and duration. The prepared piezoceramic slurry, containing barium titanate, was successfully polymerized using laser-stereolithography and its cure depth exhibited a similar response to exposure duration and fluence level as the commercial slurries. The in-plane resolution of the barium titanate-based slurry was unexpectedly high, and may be due to the opacity of the piezoelectric particles. Open architectures with millimeter sized features were successfully fabricated using laser stereolithography. Dimensional accuracy was highest for the alumina-based material system, and the inverse relationship between cured depth and in-plane resolution was reflected in the dimensions of the silica-based parts. Open architected structures further withstood thermal processing. During thermal processing, there was a greater reduction in height for all parts due to higher in-plane concentrations of ceramic particles, relative to the z-direction. Both an increase in sintering temperature and duration resulted in a uniform change of 1%, respectively, in part dimensions. Data collected in this work is to be used as a benchmark to inform formulation requirements, laser stereolithography parameter settings and thermal processing procedures for a custom ceramic slurry containing piezoelectric nanoparticles.

Proceedings Article | 27 March 2019 Presentation + Paper

Soft-matter pressure sensors for turbulence detection

James Wissman, Kaushik Sampath, Alec Ikei, Kadri Buğra Özütemiz, Carmel Majidi, Charles Rohde

Proceedings Volume 10970, 109702D (2019) https://doi.org/10.1117/12.2514358

KEYWORDS: Sensors, Liquids, Metals, Acoustics, Capacitance, Laser Doppler velocimetry, Carbon nanotubes, Resistance, Capacitors

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Proceedings Article | 13 March 2019 Presentation + Paper

Liquid metal-based bio-inspired capacitive flow sensor

James Wissman, Kaushik Sampath, Charles Rohde

Proceedings Volume 10965, 109650T (2019) https://doi.org/10.1117/12.2514355

KEYWORDS: Liquids, Sensors, Metals, Capacitance, Biomimetics, 3D printing, Kinematics, Capacitors, Analytical research

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Proceedings Article | 27 March 2018 Presentation + Paper

Reconfigurable metasurfaces for directional acoustic sensing

Charles Rohde, Mathew Guild, Alec Ikei, Jeffrey Rogers, David Calvo, Gregory Orris

Proceedings Volume 10600, 106001I (2018) https://doi.org/10.1117/12.2296029

KEYWORDS: Acoustics, Solids, Finite element methods, 3D printing, Printing, Metamaterials, Polymers, Resonators, Reflectivity, Fused deposition modeling

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Proceedings Article | 27 March 2018 Paper

Far-field superresolution imaging using shaped acoustic vortices

Matthew Guild, Jeffrey Rogers, Charles Rohde, Theodore Martin, Gregory Orris

Proceedings Volume 10600, 1060015 (2018) https://doi.org/10.1117/12.2296671

KEYWORDS: Acoustics, Super resolution, Wave propagation, Signal processing, Diffraction, Image resolution

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Proceedings Article | 5 April 2017 Paper

Acoustic vortex beam generation using a compact metamaterial aperture

Charles Rohde, Christina Naify, Matthew Guild, Theodore Martin, Jeffrey Rogers, David Calvo, Gregory Orris

Proceedings Volume 10170, 101701I (2017) https://doi.org/10.1117/12.2260164

KEYWORDS: Acoustics, Wavefronts, Antennas, Metamaterials, Phase contrast, Waveguides, Electromagnetism, Super resolution, Waveguide modes, Additive manufacturing, Resonators, Wave propagation, Receivers, Phase measurement, Finite element methods, Data modeling

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Showing 5 of 6 publications

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