Herbert Shea

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In this paper, we present miniaturized polydimethylsiloxane (PDMS)-based diaphragm dielectric elastomer actuators capable of out-of-plane displacement up to 25% of their diameter. This very large percentage displacement is made possible by the use of compliant electrodes fabricated by low-energy gold ion implantation. This technique forms nanometer-scale(More)
Photon counting is useful in space-based imagers wherever quantitative lightintensity evaluation is necessary. Various types of radiation, from cosmic rays to high-energy proton beams to gamma radiation, have an effect on the functionality and accuracy of imagers and the literature is extensive [1,2]. Techniques to maximize sensor tolerance have also been(More)
Hydraulic impedance is a critical parameter for the operation of electrospray emitters, and for preventing flooding when spraying from arrays of emitters. Controlling flow rate by tuning the flow impedance allows accessing different operating modes, such as droplet, ionic, or pulsating. We report on a method to tailor the hydraulic impedance of(More)
We report on the first ion-implanted dielectric electroactive polymer actuator that was successfully microfabricated and tested. Ion implantation is used to make the surface of the polymer locally conducting. Implanting the compliant electrodes solves the problem of how to microfabricate patterned electrodes having elasticity close to that of the insulating(More)
Biological cells modulate their behavior, express genes, proliferate or differentiate in response to mechanical strains ranging from 1% to 20%. There currently exists no technique to apply strain to many targeted individual cells in a larger culture in order to perform parallelized high throughput testing. Dielectric elastomer actuators (DEAs) are compliant(More)
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Carbon nanotubes are novel materials with unique electrical and mechanical properties. Here we present results on their atomic structure and mechanical properties in the adsorbed state, on ways to manipulate individual nanotubes, on their electrical properties and, finally, on the fabrication and characteristics of nanotube-based electron devices.(More)
With their extremely low mass and volume, low power consumption and tight integration with electronics, MEMS sensors and actuators are extremely appealing for reducing the size and mass of spacecraft without sacrificing functionality. In view of the harsh and remote environment of space, reliability and qualification is the crucial issues that are holding(More)
Debris in space present an ever-increasing problem for spacecraft in Earth orbit. As a step in the mitigation of this issue, the CleanSpace One (CSO) microsatellite has been proposed. Its mission is to perform active debris removal of a decommissioned nanosatellite (the CubeSat SwissCube). An important aspect of this project is the development of the(More)