A new microelectromechanical-systems capacitive pressure sensor with extremely high sensitivity (2.24 ¿F/kPa) is introduced. The sensor essentially consists of a small drop of mercury and a flat aluminum electrode that are separated by a 1 ¿m-thick layer of Barium Strontium Titanate (a high dielectric-constant ceramic). The assembly constitutes a parallel-plate capacitor where the surface area of the electrodes is variable to a high degree. The mercury drop is pressured by a small corrugated metal diaphragm. As the electrode area of the parallel-plate capacitor varies, a total change in capacitance of more than 6 ¿F is obtained.

This paper reports the successful creation of a new ultracapacitor structure that offers a capacitance density on the order of 100 to 200 Farads per cubic centimeter; versus the current state of the art capacitance density of 1 F/cm³. The principle behind the new ultracapacitor structure is the insertion of a few nanometers-thick layer of barium strontium titanate as an interface between an activated carbon electrode and a suitable electrolyte, such as acetonitrile or propylene carbonate. The new ultracapacitors are highly needed in hybrid vehicle applications, because any significant increase in the energy storage capability of the ultracapacitors leads to substantial improvement in the fuel efficiency of hybrid vehicles.

This research group has recently used the new technology Distributed Acoustic Sensing (DAS) for the monitoring and the measurement of airplane flutter. To the authors’ knowledge, this is the first such use for this new technology. Traditionally, the measurement of airplane flutter requires the mounting of a very large number of sensors on the wing being monitored, and extensive wiring must be connected to all these sensors. The new system and technology introduced in this paper dramatically reduces the hardware requirements in such an application: all the traditional sensors and wiring are replaced with one fiber optic cable with a diameter of 2 mm. An electro-optical system with the size of a desktop PC monitors simultaneously one or more of such fiber optic cables and detects/characterizes any mechanical disturbances on the cables. Theoretical and experimental results are given.

This paper introduces a new type of electret microphone with an excellent dynamic range (0-120 dB SPL) and excellent frequency response characteristics over the range of 20 Hz to 20 kHz. The fundamental concept behind the new microphone is the placement of a thin PTFE (Teflon) electret membrane inside the core of a toroidal coil. As the membrane vibrates in response to the sound, a very small magnetic field is created, is picked up by the coil, and is amplified by a superconducting quantum interference device (SQUID) or by a conventional FET amplifier. Analysis and experimental results show that this new transduction mechanism results in a microphone that, while physically larger than other microphones, has substantially better performance in high-bandwidth applications.

This study presents transient aspects of light wave propagation connected with spatial coherence. It is shown that reflection and refraction phenomena involve spatial patterns which are created within a certain transient time interval. After this transient time interval, these patterns act like a memory, determining the wave vector for subsequent sets of reflected/refracted waves. The validity of this model is based on intuitive aspects regarding phase conservation of energy for waves reflected/refracted by multiple centers in a certain material medium.