Abstract: There is provided a method for making blocked isocyanate trimers comprising (A) blocking at least one organic diisocyanate with at least one blocking compound, such as a monohydroxy compound and thereafter (B) heating the reaction product of step (A) in the presence of a catalyst having the general formula ##STR1## where each R is independently selected from hydrogen and lower alkyl radicals and R.sup.1 is an alkylene radical having up to about six carbon atoms; for an amount of time effective for forming blocked isocyanate trimers.

Abstract: A tracking system for measuring and recording the movements of a longwall shearer vehicle (10) includes an optical tracking assembly (B) carried at one end of a desired vehicle path and a retroreflector assembly (A) carried by the vehicle. Continuous horizontal and vertical light beams are alternately transmitted at (38) by means of a rotating Dove prism (58) to the reflector assembly (A). A vertically reciprocating reflector (34) interrupts the continuous light beams and converts these to discrete horizontal and vertical light beam images transmitted at (68) at spaced intervals along the path. A second rotating Dove prism (64) rotates the vertical images to convert them to a second series of horizontal images while the first mentioned horizontal images are left unrotated and horizontal. The images are recorded on a film (74, 104). An overlay (106) with X and Y co-ordinates may be utilized to view the images and provide a graphical representation of the vehicle's path along the longwall coal face.

Abstract: A method for fabricating a gate-source structure for a recessed-gate static induction transistor. Source impurities are implanted prior to forming the recessed gates. The recessed gates are formed by a first isotropic etching step and a second anisotropic etching step which results in a unique overhanging protective layer used to protect the walls of the grooves during implantation of gate impurities in the bottom of the grooves. Implantations are driven and activated to form gate and source regions, the protective layer is removed and metal deposited to form electrodes. The procedure minimizes the required number of masking steps and associated mask registration problems.

Abstract: A penetrometer for coal-shale interface detection for use with coal cutting equipment consisting of a reciprocating hammer having an accelerometer mounted thereon to measure the impact of the hammer as it penetrates the ceiling or floor surface of a mine. Additionally, a pair of reflectometers simultaneously view the same surface, and the outputs from the accelerometer and reflectometers are detected and jointly registered to determine when an interface between coal and shale is being cut through.

Abstract: Packaging in the form of a carrier for holding and carrying a plurality of containers such as cans, bottles, jars and the like is disclosed. The carrier comprises at least one packaging band which completely encloses a plurality of containers arranged in at least one row while incompletely enclosing the periphery of any individual container. At least one carrying band is associated with the at least one packaging band to provide means for grasping and lifting the container package. Several combinations of enclosed rows, each containing a plurality of containers, are disclosed along with appropriate carrying bands.