Abstract: A method characterized by the steps of positioning a plurality of uniformly dimensioned photovoltaic cells in registered relation with a plurality of openings formed in a planar tool for affording access to the P contact surface of each of the cells, connecting the N contact surface of alternate cells to the P contact surface of the cells interposed therebetween, removing therefrom residue of solder flux, applying to the N contact surfaces of the cells a transparent adhesive, placing a common transparent cover plate in engaged relation with the adhesive, placing a film over the circular openings for hermetically sealing the openings, and establishing a vacuum between the film and the cover plate for thus simultaneously forcing the cells into vacuum bonded relation with the cover plate.

Abstract: A bipolar voltage ramp generator applies a linear voltage through a resistor to a solar cell for plotting its current versus voltage (I-V) characteristic between short circuit and open circuit conditions, with automatic stops at the end points. The resistor serves the multiple purpose of providing a current sensing resistor, setting the full-scale current value, and providing a load line with a slope approximately equal to one, such that it will pass through the origin and the approximate center of the I-V curve with about equal distance from that center to each of the end points.

Abstract: A solar energy collector system characterized by an improved concentrator for directing incident rays of solar energy on parallel strip-like segments of a flat-plate receiver and a plurality of individually mounted reflector modules of a common asymmetrical triangular cross-sectional configuration supported for independent reorientation and defining a plurality of asymmetric vee-trough concentrators for deflecting incident solar energy toward the receiver.

Abstract: A computerized system for translating a torch head tip at a constant travel speed along a contoured workpiece including a driven skate characterized by an elongated bed, a pair of independently pivotal trucks connected to the bed in supporting relation therewith and mounted on a contoured track of an arbitrary configuration in mutually spaced relation, an axially extensible torch head manipulator arm mounted on the bed of the carriage and projected perpendicularly from the midportion thereof and having a torch head mounted at its distal end, and a real-time computerized control drive subsystem to advance the skate along the track at a variable rate for maintaining a constant speed for the torch head tip and to position the torch axis relative to a preset angle to the workpiece.

Abstract: A received, suppressed carrier, quadraphase shift key modulated (QPSK) signal is demodulated with a phase locked loop including a variable frequency, coherent reference that drives first and second channels also responsive to the QPSK signal. The channels respectively derive first and second replicas of binary signals that modulated the suppressed carrier. The replicas are combined to derive a variable amplitude error signal for controlling the coherent reference frequency. The frequency of the coherent reference is dithered at a low rate so that there is derived a relatively low level tracking error phase from the locked loop. The frequency of the coherent reference is swept when the phase of the error signal differs from the dithering phase by a predetermined value that is appreciably less than 90.degree..

Abstract: Nitramine propellants absent a pressure exponent shift in the burning rate curves are prepared by matching the burning rate of a selected nitramine or combination of nitramines within 10% of burning rate of a plasticized active binder so as to smooth out the break point appearance in the burning rate curve.