Abstract: A semiconductor diode laser is aligned to a waveguide with two sections, a first section being a passive low-loss waveguide and a second section being a Bragg grating. The first section works to increase the total cavity length l of the laser by about 1 to 2 cm. The lengthening of the cavity reduces the longitudinal mode spacing .DELTA..lambda. according to the equation .DELTA..lambda.=.lambda..sup.2 /2nl, and provides a higher average output power level because it is substantially immune to mode hop-induced fluctuations. The second section causes the output to be centered at the desired wavelength depending on the grating spacing. An array of diode lasers with an array of waveguides as described above provides a high power source with a controlled bandwidth. The high power laser array with stabilized output wavelength is used to pump a solid state laser crystal.

Abstract: A discharge control device for transferring accumulated electrostatic charge from containers used in spray painting, to a charge sink, comprising a housing having a hermetically sealed discharge chamber mounted inside. A first electrical contact for receiving an accumulated electrostatic charge is mounted in the discharge chamber in opposition to a reciprocating electrical contact for receiving and dissipating the accumulated charge from the first contact. The reciprocating contact is slidably mounted on the discharge chamber so that it moves between one position adjacent to or touching the first contact means and a second position spaced apart from the first contact. A first electrical conductor is connected between the first contact and the container, and a second conduction means is connected between the reciprocating contact means and the charge sink.

Abstract: A method of arresting delamination between and within plies of a composite laminate having layers containing a resin without significantly degrading the structural strength of the laminate characterized by emplacing within a plurality of the laminate layers having a resin, at a plurality of respective discrete locations, narrow strips of a tough adhesive having a fracture toughness greater than the fracture toughness of the resin in the respective layers of laminate. The adhesive has a Mode I critical strain energy release rate in the range of 5 inch pounds per square inch or more; for example, about 10 inch pounds per square inch. Also disclosed is a preferred method of constructing the laminate to employ this invention.

Abstract: An axial flow fan has a plurality of impeller blades spaced around a hub assembly. The leading edge of each blade overlaps completely the trailing edge of the preceding blade, and the angular spacing between the radial center lines of the blades is unequal, preferably varying in a sinusoidal pattern, so that tonal noise of the fan is effectively attenuated.

Abstract: A totally enclosed electrical machine, particularly a high power electric motor, is provided with a plate-type, crossflow, air-to-air heat exchanger which is seated on the frame of the electrical machine. Adjacent plates of the heat exchanger are modular units which define an array of ducts through which the internal air heated by the machine flows in a direction away from the machine. The ducts at opposite ends of the array provide passages for the bi-directional flow of air, such that air which is cooled in the heat exchanger is returned to the opposite ends of the machine. The heat exchanger is provided with a plenum in which air is returned to the end ducts. A baffle in the plenum distributes the air in different amounts, which vary progressively but in opposite senses, to the return ducts which communicate with the opposite ends of the machine thereby equalizing the temperature of the return air supplied to the opposite ends of the machine and providing uniform cooling of the machine.

Abstract: A system is described for transmission, storage (as by recording) and for multiplexing of both digital and analog information. The recording system includes apparatus for converting analog information into digital information having a predetermined format. Each track of the recording apparatus receives a series of encoded format words containing a plurality of ternary NRZ pulses, each represented by any one of three voltage levels; positive, negative or zero volts during a bit interval, such that the average level of each word is zero volts. The spectrum of a signal composed of a serial sequence of these format words is capable of being recorded on a magnetic tape recording track with a much higher pulse packing density than heretofore possible with conventional NRZ or other binary recording techniques.