A steering system for use with a multiple vehicle train is disclosed which permits tracking without rails of one vehicle after another. This system is particularly useful for moving conveyor systems into and out of curved paths of room and pillar underground mine installations. The steering system features an elongated steering bar pivotally connected to each of adjacent vehicles at end portions of the bar permitting angular orientation of each vehicle in respect to the steering bar and other vehicles. Each end portion of the steering bar is linked to the near pair of vehicle wheels through wheel yoke pivot arms about king pin type pivots. Movement of the steering bar about its pivotal connection provides proportional turning of the wheels to effect steering and tracking of one vehicle following another in both forward and reverse directions.

A secondary concentrator for use in receiver systems for linear focusing primary concentrators is provided with reflector wings at each end. The wings increase the capture of light rays reflected from areas adjacent the rim of a primary concentrator, increasing the apparent aperture size of the receiver as viewed from the rim of the primary concentrator. The length, tilt, and curvature of the wing reflectors can be adjusted to provide a receiver having a desired aperture aspect.

A system is provided for utilizing fines of carbonaceous materials such as particles or pieces of oil shale of about one-half inch or less diameter which are rejected for use in some conventional or prior surface retorting process, which obtains maximum utilization of the energy content of the fines and which produces a waste which is relatively inert and of a size to facilitate disposal. The system includes a cyclone retort which pyrolyzes the fines in the presence of heated gaseous combustion products, the cyclone retort having a first outlet through which vapors can exit that can be cooled to provide oil, and having a second outlet through which spent shale fines are removed. A burner connected to the spent shale outlet of the cyclone retort, burns the spent shale with air, to provide hot combustion products that are carried back to the cyclone retort to supply gaseous combustion products utilized therein. The burner heats the spent shale to a temperature which forms a molten slag, and the molten slag is removed from the burner into a quencher that suddenly cools the molten slag to form granules that are relatively inert and of a size that is convenient to handle …

A combination regenerative ring and backward Raman waveguide amplifier and a combination regenerative ring oscillator and backward Raman waveguide amplifier which produce Raman amplification, pulse compression, and efficient energy extraction from the CO/sub 2/ laser pump signal for conversion into a Stokes radiation signal. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman waveguide amplifier. The backward Raman waveguide amplifier configuration extracts a major portion of the remaining energy from the CO/sub 2/ laser pump signal for conversion to Stokes radiation.

A seal assembly comprises a tube rotatable about its longitudinal axis and having two longitudinally spaced flanges projecting radially outwardly from the outer surface thereof. Slidably positioned against one of the flanges is a seal ring, and disposed between this seal ring and the other flange are two rings that are forced apart by springs, one of the latter rings being attached to a flexible wall.