Boss is an autonomous vehicle that uses on-board sensors (global positioning system, lasers, radars, and cameras) to track other vehicles, detect static obstacles, and localize itself relative to a road model. A three-layer planning system combines mission, behavioral, and motion planning to drive in urban environments. The mission planning layer considers which street to take to achieve a mission goal. The behavioral layer determines when to change lanes and precedence at intersections and performs error recovery maneuvers. The motion planning layer selects actions to avoid obstacles while making progress toward local goals. The system was developed from the ground up to address the requirements of the DARPA Urban Challenge using a spiral system development process with a heavy emphasis on regular, regressive system testing. During the National Qualification Event and the 85-km Urban Challenge Final Event, Boss demonstrated some of its capabilities, qualifying first and winning the challenge. C 2008 Wiley Periodicals, Inc.

In order to get poly(vinylidene fluoride) (PVDF) films containing high beta-phase content, multiwalled carbon nanotubes (MWCNTs) were blended with PVDF. For drawn samples, the content of piezoelectric beta-form crystal was increased with MWCNT addition due to the rapid crystallization rate offered by the nucleating action of MWCNT, but soon reached a plateau. Poling on the drawn samples helps additional beta-phase formation when the added MWCNT content was less than 0.2 wt%; at this MWCNT amount, almost pure beta-phase crystal was obtained. More MWCNT addition induced depolarization to reduce the beta-phase content. Undrawn samples show monotonous increase of beta-phase content with MWCNT amount when subjected to poling.

We prepared poly(vinylidene fluoride) (PVDF)/multiwalled carbon nanotube (MWCNT) nanocomposites using the electrospinning process and investigated the effects of varying the MWCNT content, as well as the additional use of drawing and poling on the polymorphic behavior and electroactive (piezoelectric) properties of the membranes obtained. Fourier transform infrared spectroscopy and wide-angle X-ray diffraction revealed that dramatic changes occurred in the β-phase crystal formation with the MWCNT loading. This was attributed to the nucleation effects of the MWCNTs as well as the intense stretching of the PVDF jets in the electrospinning process. The remanent polarization and piezoelectric response increased with the amount of MWCNTs and piezoelectric β-phase crystals. A further mechanical stretching and electric poling process induced not only highly oriented β-phase crystallites, but also very good ferroelectric and piezoelectric performances. In the drawn samples, the interfacial interaction between the functional groups on the MWCNTs and the CF 2 dipole of PVDF chains produced a large amount of βphase content. In the poled samples, the incorporation of the MWCNTs made it easy to obtain efficient charge accumulation in the PVDF matrix, resulting in the conversion of the α-phase into the β-phase as well as the enhancement of remanent polarization and mechanical displacement.

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The sedimentation stability of a carbonyl iron (CI)-based magnetorheological (MR) fluid was improved by wrapping CI particles with a polystyrene (PS) foam layer. The PS layer on the CI particles was synthesized via conventional dispersion polymerization and was subsequently foamed using a supercritical carbon dioxide fluid to produce core−shell structured particles. The density of particles decreased after the PS-layer wrapping and subsequent PS-layer foaming. The surface morphology was observed by scanning electron microscope (SEM) and the specific surface areas were determined by Brunauer−Emmett−Teller (BET) adsorption measurements. Both modifications (PS-layer wrapping and foaming) increased the surface roughness of the particles, yet preserved particle's spherical shape. The effect of the volume expansion after modification on the magnetorheological properties was investigated by using a vibrating sample magnetometer (VSM) and a rotational rheometer. All suspensions tested presented similar MR behaviors with the only difference in their yield stress strengths. Finally, the sedimentation properties of the synthesized particles was examined using a Turbiscan apparatus. MR fluids containing the newly developed CI particles wrapped with the foamed PS layer exhibited remarkably improved stability against sedimentation due to the reduced mismatch in density between the particles and the carrier medium.