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Herbert Shea

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Publications associées (163)

An array of 100 μm × 100 μm dielectric elastomer actuators with 80% strain for tissue engineering applications

Herbert Shea, Samin Akbari

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 ord ...

Elsevier2012

LTCC integrated miniature Rb discharge lamp module for stable optical pumping in miniature atomic clocks and magnetometers

Thomas Maeder, Peter Ryser, Herbert Shea, Vinu Lalgudi Venkatraman, Fabrizio Vecchio

We report here on an integrated mini-lamp module (15x26x4 mm3) with a microfabricated rf-powered Rb dielectric barrier discharge (DBD) lamp (10x10x3 mm3) positioned on top of a 0.6 mm thick (thickness adjustable) 4-layer LTCC (Low Temperature Co-fired Cera ...

IEEE2012

Dispensing and Hermetic Sealing Rb in a Miniature Reference Cell for Integrated Atomic Clocks

Thomas Maeder, Peter Ryser, Herbert Shea, Vinu Lalgudi Venkatraman, Fabrizio Vecchio

An innovative method for filling and sealing the reference cell for a Rubidium (Rb) integrated atomic clock is presented. We used a simple, low-temperature solder sealing technique for producing mini-cells of the size of 12 x 10 x 2 mm, suitable for Rb min ...

Elsevier2011

Electrical conductivity and Young's modulus of flexible nanocomposites made by metal ion implantation of Polydimethylsiloxane: the relationship between nanostructure and macroscopic properties

Muhamed Niklaus, Herbert Shea

The mechanical and electrical properties of nanocomposites created by gold and titanium implantation into Polydimethysiloxane (PDMS) are reported for doses from 1015 at/cm2 to 5x1016 at/cm2, and for ion energies of 2.5 keV, 5 keV and 10 keV. TEM cross-sect ...

Elsevier2011

Vibration and shock reliability of MEMS: modeling and experimental validation

Herbert Shea, Maurizio Tormen, Robert Andrew Lockhart, Subramanian Sundaram

A methodology to predict shock and vibration levels that could lead to the failure of MEMS devices is reported as a function of vibration frequency and shock pulse duration. A combined experimental–analytical approach is developed, maintaining the simplici ...

Institute of Physics2011

Enhancement of actuation ability of ionic-type conducting polymer actuators using metal ion implantation

Herbert Shea

In this study, we present the results and implications of an experimental study into the effect of gold-ion implantation on the actuation performance of ionic-type conducting polymer actuators, represented here by cantilevered tri-layer polypyrrole (PPy) a ...

Elsevier2011

Array of lenses with individually tunable focal-length based on transparent ion-implanted EAPs

Samuel Rosset, Muhamed Niklaus, Herbert Shea

We report on the fabrication and characterization of 2x2 arrays of mm-diameter PDMS lenses whose focal length can be electrically tuned. Dielectric elastomer actuators generally rely on carbon powder or carbon grease electrodes, which are not transparent, ...

Spie-Int Soc Optical Engineering, Po Box 10, Bellingham, Wa 98227-0010 Usa2010

3-dimensional electrode patterning within a microfluidic channel using metal ion implantation

Samuel Rosset, Muhamed Niklaus, Herbert Shea, Demetri Psaltis, Jae-Woo Choi, James Adleman

The application of electrical fields within a microfluidic channel enables many forms of manipulation necessary for lab-on-a-chip devices. Patterning electrodes inside the microfluidic channel generally requires multi-step optical lithography. Here, we uti ...

Royal Society of Chemistry2010

Arrays of EAP micro-actuators for single-cell stretching applications

Herbert Shea, Samin Akbari

Mechanical stimuli are critical for the development and maintenance of most tissues such as muscles, cartilage, bones and blood vessels. The commercially available cell culture systems replicating the in vivo environment are typically based on simple membr ...

Spie-Int Soc Optical Engineering, Po Box 10, Bellingham, Wa 98227-0010 Usa2010

MEMS for space

Nico de Rooij, Wilfried Noell, Herbert Shea, Danick Briand, Sebastian Gautsch

Future space exploration will emphasize on cost effectiveness and highly focused mission objectives. Missions costs are directly proportional to its total weight, thus, the trend will be to replace bulky and heavy components of space carriers, communicatio ...

2009

Tailoring the hydraulic impedance of out-of-plane micromachined electrospray sources with integrated electrodes

Renato Krpoun, Herbert Shea

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 a ...

American Institute of Physics2009

Fabrication and Testing of a MEMS Based Earth Sensor

Herbert Shea, Kaustav Ghose

We present a novel MEMS inertial sensor that directly measures the gravity gradient in order to sense the relative orientation of a satellite with respect to the Earth. An Earths ensor provides an orbiting satellite with a vector towards the Earth center. ...

2009

A micromachined earth sensor based on measuring the gravity gradient torque

Herbert Shea, Kaustav Ghose

We present the fabrication and testing of a novel MEMS inertial sensor that directly measures the gravity gradient in low Earth orbit in order to sense the relative orientation of a satellite with respect to the Earth. Instead of the current Earth sensing ...

American Soc Mechanical Engineers, Three Park Avenue, New York, Ny 10016-5990 Usa2009

SPACE: the spectroscopic all-sky cosmic explorer

Rachel Grange, Herbert Shea, Stewart Cole, Fabio Finelli, Jean-Paul Richard Kneib, Yi Wang

We describe the scientific motivations, the mission concept and the instrumentation of SPACE, a class-M mission proposed for concept study at the first call of the ESA Cosmic-Vision 2015–2025 planning cycle. SPACE aims to produce the largest three-dimensio ...

Springer Verlag2009

Electrical breakdown at low pressure for planar microelectromechanical systems with 10- to 500-micron gaps

Herbert Shea

An experimental study of the dc breakdown voltage for planar MEMS interdigitated aluminum electrodes with gaps ranging from 10 to 500 micron is presented. Unlike most research on the breakdown in MEMS electrodes that was performed at atmospheric pressure, ...

2009

Radiation sensitivity of microelectromechanical system devices

Herbert Shea

The sensitivity of microelectromechanical system (MEMS) devices to radiation is reviewed, with an emphasis on radiation levels representative of space missions rather than of operation in nuclear reactors. As a purely structural material, silicon has shown ...

2009

A Variable Dynamic Range Single-Photon Imager Designed for Multi-Radiation Tolerance

Cristiano Niclass, Edoardo Charbon, Noémy Scheidegger, Herbert Shea, Lucio Carrara, Matthew Fishburn

2009

Large-Stroke Dielectric Elastomer Actuators With Ion- Implanted Electrodes

Samuel Rosset, Muhamed Niklaus, Herbert Shea

In this paper, we present miniaturized polydimethyl- siloxane (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 com ...

Institute of Electrical and Electronics Engineers2009

Metal Ion Implanted Compliant Electrodes in Dielectric Electroactive Polymer (EAP) Membranes

Samuel Rosset, Muhamed Niklaus, Herbert Shea

One of the key factors to obtain large displacements and high efficiency with dielectric electroactive polymer (DEAPs) actuators is to have compliant electrodes. Attempts to scale DEAPs down to the mm or micrometer range have encountered major difficulties ...

Trans Tech Publications Ltd2009

Ion-implanted compliant electrodes used in dielectric electroactive polymer actuators with large displacement

Samuel Rosset, Muhamed Niklaus, Herbert Shea

Metal ion implantation is shown here as an effective technique to fabricate highly compliant electrodes at room temperature on polymer substrates. By implanting 5 keV gold ions in polydimethylsiloxane we have fabricated micron-scale electrodes that conduct ...

Elsevier Science, Reg Sales Off, Customer Support Dept, 655 Ave Of The Americas, New York, Ny 10010 Usa2009

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