Microplasma microphones

It is shown experimentally that a microplasma created by a microstructured electrode array is sensitive to sound pressure. In this paper, two electrode architectures are used to create the microplasma. The sensitivity of these microplasma microphones, close to 0.4 nA/Pa, is estimated using a waveguide and a calibration method by comparison with a reference microphone. An empirical expression of the acoustic pressure sensitivity of microdischarges is proposed. The predictions of this empirical model are in good agreement with the experimental data.

Micron-Scale Diagnostics for Through-Plane Transport Phenomena in Porous Electrodes

This paper presents the development of a new method for characterizing the electrochemistry and transport phenomena in the porous electrodes of polymer electrolyte membrane fuel cells (PEMFCs). The new method uses a unique microstructured electrode scaffold (MES) that provide an architecture for obtaining measurements at discrete points through the thickness of an electrode. This paper reports on the design, fabrication and initial testing of an MES for measuring ionic potential across the thickness of a PEMFC’s cathode. The new fuel cell hardware and reference electrodes (REs), which gather electrolyte potential measurements through the thickness of the electrode via the MES, have been tested for accuracy and repeatability. The use of hydrogen oxidation reaction (HOR) REs versus oxygen reduction reaction (ORR) REs is analyzed and discussed. Polarization data was also gathered and the REs are used to separate the half-cell potentials. Finally, the preliminary fabrication of an MES and a micro-structural analysis are discussed.