Abstract: The invention is directed to an apparatus and method for curing polymeric materials by use of a closed-loop, automatic process control technique. A dielectric monitoring device (15) senses the electrical characteristics which are analogous to viscosity changes taking place in an uncured or partially cured polymeric material (10) while heat is applied thereto. The generated analog signal, which changes in response to variations in the capacitance and dissipation of the polymeric material, is fed into a microcomputer (21) which determines from the direction and amplitude of the generated wave form both the maximum and minimum levels of capacitance and dissipation developed. When a predetermined condition is reached, the microcomputer (21) sends a control signal to processing equipment (24,25) to apply pressure, heat and/or vacuum to the polymeric material (10) at or near the onset of gelation but prior to the hardening point.

Abstract: A blasting machine utilizing sublimable particles comprising forming means (14) for producing particles having a substantially uniform length thereto, dispensing means (32) for receiving the particles and for introducing the particles into a low pressure transport gas flow, and a nozzle (44) for accelerating the particles and having a high pressure, low velocity gas flow coupled to it, the nozzle (44) being adapted to convert the high pressure, low velocity gas flow into a low pressure, high velocity gas flow. A conduit (142) coupled to the nozzle (44) and the dispensing means (32) receives the particles and introduces the particles into the low pressure, high velocity gas flow within the nozzle (44) which entrains the particles and accelerates them to a high exit velocity.

Abstract: A sample of polymeric composite material is cured using conventional curing methods. The optimum time during the cure cycle for applying pressure to the sample is determined by standard resin advancement measuring techniques. A dielectrometer monitoring device (15) is then attached to another material of the same type which is cured under the same conditions to develop an analog signal denoting variations in dissipation of the material. The dissipation curve characteristically has a first and second maximum value, with the latter occurring in the general vicinity of the optimum time for applying pressure for a particular frequency. Thus by changing the frequency, the dissipation is shifted along the time axis so that the second maximum coincides with the optimum time for applying pressure. The generation of a readily recognizable and repeatable feature on the analog wave form, a minimum or maximum, is a prerequisite to triggering process control functions.

Abstract: An acoustical silencer for a gas passage or exhaust duct for a gas turbine engine, which is composed of three parts. The first comprises an absorptive surface to absorb incident low frequency sound the second comprises an acoustically lined duct attenuating high frequency sound transmitted therethrough. The entrance to the first part and the entrance to the second part are essentially coplanar. The third part is a horn-shaped plenum or conical diffuser to contain the flow and distribute the sound over the entry surface of the first part and the entrance to the second part. The entrances to both the first and second parts, being coplanar, present acoustically parallel paths to sound impinging on their common plane. The input impedances of the absorptive surface of the first part and the entrance to the second part are adjusted such that a disproportionately larger share of the incident low frequency acoustical energy passes into the first part and is dissipated.

Abstract: Apparatus for attenuating waves on the surface of a fluid and for providing a protective calm area is provided comprising means (20) for causing the waves to break, means (30) for directing the broken waves to induce a downward flow of surface fluid, means (34) for discharging the downward flow of surface fluid a preselected distance below the surface of the fluid, and means (48,50,60,62,64) for orienting the wave breaking means to provide a preselected orientation of the wave breaking means relative to the resultant flux vector of the energy of the waves. In a particular embodiment, one or more submerged refractive structures (20) each in the form of a dome-shaped shell, are provided to cause the waves to break. Guide vanes (36) direct the broken surface waves into a centrally disposed vertical standpipe (34) where the fluid flows downward and is then discharged at the bottom of the shell.

Abstract: A door seal for use on an aircraft in which one portion of a striker (22) is attached to the door (12) and a second portion of the striker (34) is attached to the door frame (14) and in which one portion of a lip (18) for engaging the striker is attached to the door (12) and a second portion of the lip (16) is attached to the door frame (14), the two lip portions (16, 18) being configured to overlap one another and to mate with the two striker portions (22, 34) and with one another when the door (12) is closed, whereby the lip (18) on the door (12) transitions to a lip (16) on the door frame (14).

Abstract: Apparatus for extracting material floating on the surface of a fluid having waves thereon is provided comprising means (20) for causing the waves to break, means (36) for directing the broken waves to induce a downward flow of surface fluid and the material thereon, means (34) for discharging the downward flow of fluid and said material a preselected distance below the surface of the fluid, and means (20, 22) for containing the discharged material. In a particular embodiment, a submerged refractive structure in the form of a dome-shaped shell (20) is provided to cause the waves to break. Guide vanes (36) direct the broken surface waves into a centrally disposed vertical standpipe (34) where the fluid and the entrained floating material flows downward and is then discharged at the bottom of the shell. The material accumulates at the upper interior portion (22) within the shell. An access opening (50) is provided through the wall of the shell to facilitate removal of the material accumulated within the shell.

Abstract: A noise control device which relies upon retroreflection for sound attenuation. The device comprises an array of corner reflectors recessed into a surface and forming a sound retroreflecting panel. This cavitated surface provides the desired retroreflection of impinging sound waves so as to preclude undesirable onward propagation. The invention is particularly suitable for noise control applications in the presence of severe environmental conditions, and may also be used in combination with sound absorbing materials.

Abstract: An improved wind turbine in which the tip portions of the blades are variable in pitch and are cyclically varied in pitch to control the yaw of the rotor and to relieve bending moments on the blades and are collectively varied in pitch to relieve bending moments on the blades and to maximize the power output of the turbine at a selected constant rotor speed.

Abstract: The invention relates to a device for detecting transitory and repetitive light signals from a radiant energy source. The invention comprises a detector means for detecting the light signals and for providing output signals indicative of the presence thereof, first indicator means coupled to the detector means for providing a continuous indication of the initial presence of the light signals and second indicator means for providing an indication of the repetition rate of the light signals. In a particular embodiment, a video amplifier circuit is coupled to a detector circuit to provide an amplified output and a comparator circuit is coupled to the video amplifier circuit and senses the video amplifier circuit output signals above a specified level and produces standard logic level output signals. The output signals from the comparator circuit are coupled to a first indicator circuit incorporating a first light-emitting diode which provides a continuous indication of the initial presence of the light signal.

Abstract: A resinous material suitable for the fabrication of laminated structures comprising a first layer of resin and at least one second layer of filled resin contiguous with the first layer, the second layer being flowable under a compressive force. In the manufacture of a reticulated laminated structure of substantially uniform thickness, the thickness of the second layer varies in accordance with the number of first layers overlying one another at crossover nodes in the reticulated structure, with the second layer flowing from between the plies of the first layer at the nodes due to compressive forces applied to achieve such substantially uniform thickness.

Abstract: An improved cruise speed control system for commercial jet aircraft is described. The basic control terms for the pitch loop are altitude error, altitude rate and washed-out speed or Mach. The basic control terms for the speed loop are Mach error, Mach rate and integrated Mach error. Other speed loop functions include a gain term which increases at low engine response rates, based on either engine rpm or engine pressure ratio (EPR), to compensate for throttle linkage hysteresis, a versine term to compensate for increased drag in turns, an inner EPR loop for damping the outer speed loop, a variable gain term as a function of Mach error to facilitate changes of commanded Mach, and a switch to disconnect Mach error and Mach rate and to increase the nominal value of EPR during periods of air turbulence.

Abstract: A joggling machine including a joggling tool for forming an indentation in a workpiece comprising means for securing the workpiece, means for heating the workpiece to a preselected temperature, means for moving the joggling tool and the workpiece into proximity with one another and means for actuating the joggling tool. Interlocks and circuitry are provided to effect safe automatic sequencing of the joggling machine. A universal form die and a multiple chambered magazine assist in the efficient operation of the joggling machine.

Abstract: An improved humidification system for jet-powered commercial aircraft comprising an evaporator adapted to add moisture to a gas flow, a gas flow control system for applying to the evaporator a gas flow having an internal energy sufficient to vaporize the moisture and a temperature measuring system for measuring the temperature of the gas flow exiting from the evaporator for regulating the amount of moisture added to the gas flow so as to maintain the evaporator exit temperature constant is disclosed.

Abstract: A sound absorbing structure for a flow duct composed of a bundle of parallel, terminated, acoustical waveguides. The bundle of waveguides is cut obliquely so that the individual waveguides vary substantially in length along the cut. The bundle is arranged within a structure which is revolvable about its longitudinal axis. The exterior surface of the structure is spaced from the interior wall of the duct. The longitudinal axis of each of the waveguides is located substantially perpendicular to the axis of revolution. The structure revolves during passage of gas through the duct.

Abstract: A noise barrier wall having a transition area in the region of at least one unbounded edge and which employs controlled diffraction of sound to enhance the sound reducing properties thereacross. The transition area of the noise barrier is provided with either a row of absorptive shaped splitter panels, or a row of pickets, or other means of controlled transparency which provide acoustical shadowing equal to or greater than that of a solid wall for the frequency regions of interest.

Abstract: A microcomputer based system which provides a fast, error-free method of electrical harness fabrication and testing. Each connector into which the harness will be wired is mounted on a receptacle containing a multiplex transponder, a plurality of which are in turn connected in parallel through a common data cable to a controlling computer. A video display is provided for interaction between the operator and the computer. As each wire is connected between the appropriate connector pins, the computer, through the common cable and multiplex transponders, measures the connection resistance. Error messages and wiring information are displayed. Each multiplex transponder comprises a plurality of analog multiplexer/demultiplexer parts for connecting a common transmit data line in the connecting ribbon cable to any predetermined connector pin, and for connecting any connector pin to the common receive line of the connecting cable to allow testing the resistance between any electrical points.

Abstract: A broadband sound attenuating, acoustically lined, duct of varying cross-sectional shape but in the usual case having a constant cross-sectional area, and wherein the duct liner is configured to maintain an essentially constant acoustic resistance and scaled acoustic reactance throughout provided by means of changes in the effective depth of the liner. Design tradeoffs permit some variation in the cross-sectional area of the duct with concomitant changes in liner properties. In all cases, the duct is designed so that every section along its major axis is optimally tuned to absorb most efficiently some part of the frequency spectrum of interest. The device is particularly suitable for sound suppression of jet aircraft engines.