—by Richard Mandel

Bridgestone/Firestone Vehicle Systems introduced the first aftermarket applications utilizing DUAL RATE Air Spring technology and the Intelliride control-system developed by Firestone Industrial Products. PraxisAdvanced Suspensions allows drivers to control performance with the “push of a button” on a cockpit-mounted control-module, providing a choice of three fully engineered and tuned operating modes — touring, sport, or track. Vehicle performance and appearance are transformed without resorting to the time-consuming and costly necessity of physically swapping-out parts. In touring mode, the Praxis suspension system has been engineered to replicate the character of the factory-produced vehicle. Ride and handling are finely balanced to provide a car that is comfortable for long-distance touring or weekday commutes. In sport mode, the vehicle transforms to accommodate a more aggressive use by driving enthusiasts. Handling response is dramatically sharpened to suit spirited driving situations. The Praxis system, in sports mode, lowers ride-height by 25 mm. Spring rate is adjusted by engaging the progressive zone of the air spring piston, and damping is adjusted to a more aggressive setting. The track mode setting transforms the vehicle more radically. Ride-height is lowered 50 mm, damping performance is increased to precisely control body motions, and spring-rate is nearly doubled by adjusting the remote reservoir volume. The track mode is best suited for autocross and track events, and is not recommended for highway use. The Praxis suspension system will debut on the Subaru WRX platform at the SEMA show on November 5, 2003. Bridgestone/Firestone—connect directly to their website at www.rsleads.com/302df-100

In the 2 January issue of Nature, Philips and the University of Amsterdam describe the invention of the first electroluminescent material that produces either red or green light, depending on the voltage applied to it. Normally, electroluminescent materials emit light of a fixed color, determined by the energy of the excited state (bandgap) of the material. This means that any multi-color device needs areas or pixels made of different materials. The new material allows switching the emitted light between two colours depending on the direction of the applied current flow. In other words, a single pixel or area is able to radiate light in two different colors. The material is a homogeneous mix of a semiconducting polymer and a metal complex, each with a different energy of the excited state. Polymer-based electroluminescent materials combine the advantages of polymers (flexibility, low weight, easy processability) with excellent viewing characteristics (high brightness, no viewing angle dependency, very good video representation) and a low power consumption. For direction dependence, a non-symmetric device is needed, so a single layer of the material is sandwiched between electric contacts of different materials, one of gold and one of indium-tin-oxide. When a positive voltage is applied to the ITO electrode (forward bias), only the light-emission process of the metal complex is triggered and the characteristic red emission of the complex is observed. Upon reversing the bias voltage on ITO, the light-emission process in the metal complex ceases, and the excited state of the polymer is populated. The device now emits green light, corresponding to the bandgap of the polymer. Both colors are well saturated, meaning that they are not mixed with other colors. This type of material enables very simple constructionof color switches (e.g. for signalling purposes), because the entire device area only has to be coated with one material to display both colours. In the fabrication of full-color light-emitting displays, only pixels of two instead of three materials would be needed, a significant simplification in manufacturing. Moreover, both types of devices become brighter, since at any time a larger part of their surfaces actually radiates light. The material could also be used for solid-state lighting applications based on electroluminescent layers, as the new material leads to significant enhancement of brightness at improved color saturation. Philips—connect directly to their website at www.rsleads.com/302df-101