Abstract: A zip line includes a substantially rigid track supported above a ground surface by a plurality of supports, a trolley which moves along the track, and a rider support suspended from the trolley. The track is comprised of a plurality of track segments connected together such that adjacent track segments have substantially no freedom of movement relative to each other, and such that adjacent track segments present a substantially smooth, continuous, and uninterrupted surface. The track includes a run and a flange extending upwardly from the run. The trolley comprises a frame having upper wheel mounts to which first and second upper wheels are rotatably mounted. The first upper wheels are oriented such that they engage an upper surface of the track run and the second upper wheels are oriented such that they will engage the track flange upon rotational movement of the trolley relative the track run.

Abstract: A zip line includes a substantially rigid track supported above a ground surface by a plurality of supports, a trolley which moves along the track, and a rider support suspended from the trolley. The track is comprised of a plurality of track segments connected together such that adjacent track segments have substantially no freedom of movement relative to each other, and such that adjacent track segments present a substantially smooth, continuous, and uninterrupted surface. The track includes a run and a flange extending upwardly from the run. The trolley comprises a frame having upper wheel mounts to which first and second upper wheels are rotatably mounted. The first upper wheels are oriented such that they engage an upper surface of the track run and the second upper wheels are oriented such that they will engage the track flange upon rotational movement of the trolley relative the track run.

Abstract: A method is disclosed for purifying aluminum nitride produced by carbothermal reaction of aluminum oxide, carbon and nitrogen. Precursor pellets including aluminum oxide and carbon are exposed to nitrogen under conditions sufficient to carbothermally produce aluminum oxide, thereby producing aluminum nitride pellets having surface portions relatively rich in thermal conductivity-lowering and color-causing impurities compared to core portions of the aluminum nitride pellets. Significant amounts of the surface portions are thereafter removed to thereby significantly increase the purity of the aluminum nitride pellets.

Abstract: An overhead transportation system comprising for a depending and longitudinally traversible vehicle an overhead trackway as a pair of longitudinally slottedly vented tubular conduits maintained above the earth's surface with a series of pillars and having an overlying protective shield. The vehicle powering means comprises a pair of co-traversible jet engines situated within respective conduits and connected to the underlying vehicle with a dual-arms hangar means along which arms the engines' fuel-line extends. The trackway is lubricated from a longitudinally extending lubeline with syncronizeably operated nozzles spaced therealong and communicating with the conduit innerwall, and a longitudinally extending troughline collects the liquid lubricant, there being provision for re-cycling the lubricant for high-pressure re-injection into the conduits through said lubeline nozzles.