Abstract: A chopped molecular beam mass spectrometry measuring system (11, 12, 13, 14, 20) has its measurement time multiplexed (25, 26). The chopping of the molecular beam is synchronized with the multiplexing (chopper 21, OR gate 32, phase detector 35 and voltage controlled oscillator 36). Means 34 are provided for phase shifting the chopper 21 with respect to the multiplexing. A four channel amplifier 26 (disclosed in detail in FIGS. 3 and 4) is provided for independently varying the baseline and the amplitude in each channel of the multiplexing.

Abstract: A new class of ethynyl-terminated oligomers and the process for preparing same are disclosed. Upon the application of heat, with or without a catalyst, the ethynyl groups react to provide crosslinking and chain extension to increase the polymer use temperature and improve the polymer solvent resistance. These improved polyesters are potentially useful in packaging, magnetic tapes, capacitors, industrial belting, protective coatings, structural adhesives and composite matrices.

Abstract: A light-weight, economical device to alleviate a plurality of difficulties encountered in walking by a victim suffering from a drop foot condition. A legband girdles the leg below the knee and above the calf providing an anchor point for the upper end of a ligament having its lower end attached to a toe of a shoe or a toe on the foot. The ligament is of such length that the foot is supported thereby and retained in a normal position during walking.

Abstract: Ethynyl and substituted ethynyl-terminated polysulfones and a process for preparing the same are disclosed. These polysulfones are thermally cured to induce cross-linking and chain extension, producing a polymer system with improved solvent resistance and use temperatures. Also disclosed are substituted 4-ethynylbenzoyl chlorides as precursors to the substituted ethynyl-terminated polysulfones and a process for preparing the same.

Abstract: This invention is a method for providing an impression profile in a reference standard material utilized in inspecting critically stressed components with pulsed ultrasound. A die stamp (10) having an I letter, reference numeral (36), is used to impress a reference material (50) having a surface (52). The die stamp is placed against the surface (52) and struck with an inertia imparting member to impress the I in the reference standard material. Upset (54) may appear on the surface (52) as a result of the impression and is removed to form a smooth surface (52). The stamping and upset removal is repeated until the entire surface area of a depth control platform (30) on the die stamp uniformly contacts the material surface (52). The I impression profile in the reference standard material (50) is utilized for reflecting pulsed ultrasonic beams as a means for inspecting ultrasonically.

Abstract: The invention relates to a tetrahedral beam that can be compactly stowed, sequentially deployed, and widely manipulated to provide a structurally sound yet highly maneuverable truss structure. The present beam is comprised of a plurality of repeating units comprised of tandem tetrahedra sharing common sides. Tetrahedra are comprised of fixed length battens 12 joined by joint 14 into equilateral triangles called batten frames. Apexes of adjacent triangles are interconnected by longerons 16 having mid-point folding hinges 20. Joints 14 are comprised of gussets 24,34 pivotably connected by links 25. Joints 14 permit two independent degrees of rotational freedom between joined adjacent batten frames, and provide a stable structure throughout all stages of beam deployment, from packaged configuration to complete deployment. The longerons and joints can be actuated in any sequence, independently of one another. The present beam is well suited to remote actuation.

Abstract: A dual structure aerospace vehicle 10 having an aeroshell structure 11 and an internally disposed separable and reusable integral tank/thrust structure 13 is disclosed. Tank/thrust structure 13 is insulated for cryogenic fuels and the cavity 24 within aeroshell 11 is insulated from the tank/thrust structure (FIG. 2). An internal support ring 26 within cavity 24 serves as attachment for lugs 30 on tank/thrust structure 13 via double hinges 50 (FIGS. 3 and 4). The aft end of tank/thrust structure 13 is provided with rocket engines and exit nozzles 33, 34, 35 with trunnion support 37 supporting the tank/thrust structure within aeroshell 11.

Abstract: A process of endcapping a polyimide system with an endcapping agent in order to achieve a controlled decrease in molecular weight and melt viscosity along with predictable fracture resistance of the molded products is disclosed. The uncapped system is formed by combining an equimolar ratio of 4,4'-bis(3,4-dicarboxyphenoxy) diphenylsulfide dianhydride (BDSDA) and 1,3-bis(aminophenoxy)benzene (APB) dissolved in bis(2-methoxyethyl)ether. The endcapped system is formed by dissolving APB in bis-(2-methoxyethyl)ether, adding the endcapping agent, and then adding the BDSDA. By varying the amount of endcapping from 0 to 4%, molecular weight is decreased from 13,900 to 8660. At a processing temperature of 250.degree. C., there is a linear relationship between molecular weight and viscosity, with the viscosity decreasing by two orders of magnitude as the molecular weight decreased from 13,900 to 8660. A greater drop in viscosity is noted at higher temperatures.

Abstract: A laser velocimeter covariance processor which calculates the auto covariance and cross covariance functions for a turbulent flow field based on Poisson sampled measurements in time from a laser velocimeter. The device will process a block of data that is up to 4096 data points in length and return a 512 point covariance function with 48-bit resolution along with a 512 point histogram of the interarrival times which is used to normalize the covariance function. The device is designed to interface and be controlled by a minicomputer from which the data is received and the results returned. A typical 4096 point computation takes approximately 1.5 seconds to receive the data, compute the covariance function, and return the results to the computer.

Abstract: High temperature polyimide film laminates and a process for fabricating large-area, void-free polyimide laminate structures wherein multiple-ply polyimide film laminates may be constructed without decreasing the individual film strength and wherein layers of metal foil may be laminated between polyimide film layers to yield a flexible high temperature resistant structure having capabilities for use as flexible electric circuits, in aerospace applications, and the like.

Abstract: A device which corrects aerodynamic spin wherein a parachute 38 exerts anti-spin forces on an aircraft 10 to effect spin recovery. The dual parachute towlines 30 and 32 are each attached to the parachute 38 and are attached to the rear fuselage equidistant to and on opposite sides of the aircraft centerline, at 25 and 27. As the parachute 38 is deployed during spin, the parachute force 40 acts through only the towline 30, and exerts its force outboard of center on the aircraft 10. As a result, the parachute exerts not only an anti-spin torque, but additionally causes the aircraft to roll, creating a gyroscopic anti-spin rolling moment. The additional anti-spin rolling moment facilitates spin recovery by permitting a relatively smaller parachute to accomplish spin recovery equivalent to that of a larger parachute attached to the center of the rear fuselage.

Abstract: A method for determining hydrocarbon conversion factors for a flowmeter 17. A mixture of air, O.sub.2 and C.sub.x H.sub.y is burned and the partial pressure of O.sub.2 in the resulting gas is forced to equal the partial pressure of O.sub.2 in air. The flowrate of O.sub.2 flowing into the mixture is measured by flowmeter 13 and the flowrate of C.sub.x H.sub.y flowing into the mixture is measured by the flowmeter 17 conversion factor is to be determined. These measured values are used to calculate the conversion factor.

Abstract: An improved mechanical extensometer for use with a constant load creep test machine 10, wherein the dead weight of the extensometer is counterbalanced by two pairs of weights 70,90 and 80,100 connected through a pulley system 68, 78, 88 and 98 to rod extension 55,56 and 59,60, leading into the furnace 20 where test sample S is undergoing elevated temperature (above 500.degree. F.) tensile testing. Novel gripper surfaces, conical tip 119 and flat surface 122, are provided in each sample engaging platens 38 and 40 to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

Abstract: A device which increases the energy efficiency of aircraft wherein a wingtip pusher propeller 12 is positioned aft of the wingtip 18 to rotate in the crossflow of the wingtip vortex. The propeller 12 rotates against the vortex swirl creating additional thrust from and attenuating the wingtip vortex by simultaneously extracting energy from the vortex and converting it to propeller blade-induced thrust while injecting its high energy wake into the vortex axial flow to dissipate the vortex. As a result, the device increase aircraft fuel efficiency by simultaneously increasing thrust and decreasing vortex induced drag. By attenuating the vortex safety to following aircraft is maximized.

Abstract: A device for fastening a temporary replacement heat shield tile to the strain isolation pad of a space vehicle is disclosed. An internally threaded, flanged cylinder 20 is rotatably connected to a threaded brass plug 18 through a flanged aluminum sleeve 16 to form the device. The device is adhesively attached to the replacement tile 12 before using. In using the device, the tile containing the device is placed against the strain isolation pad 14 of the space vehicle such that the flanged portion of the flanged cylinder rests against the strain isolation pad. This flanged portion, which consists of a plurality of `L` shaped blades 41-44, is then rotated into the strain isolation pad. The brass plug is then rotated with respect to the flanged stainless steel cylinder to draw the tile snuggly against isolation pad and thus complete the fastening process.

Abstract: This device for inductively heating and fusing thermoplastics includes an alternating current passing through a tank circuit, the inductor member of the tank circuit being wrapped around a curved pole piece of a ferromagnetic material. The magnetic flux arising within the inductor coil member flows to the ends of the pole piece and into a screen placed between the materials to be joined. The flux induces a current in the screen, and heat is generated to melt the thermoplastics together. Because only 30-150 watts of power are passed through the tank circuit, a wire which will remain cool under operational wattage may be selected, making air or fluid cooling unnecessary.

Abstract: A device for connecting, rotating and locking together a pair of structural half-columns 11 is disclosed. The device is composed of an identical pair of cyclindrical hub assemblies 12,12a connected at their inner faces by a spring loaded hinge 20; each hub assembly having a structural half-column attached to its outer end. Each hub assembly has a spring loading locking ring 14,14a member movably attached adjacent to its inner face and includes a latch 32,32a member for holding the locking ring in a rotated position subject to the force of its spring. Each hub assembly also has a hammer 36,36a member for releasing the latch on the opposing hub assembly when the hub assemblies are rotated together. The spring loaded hinge connecting the hub assemblies rotates the hub assemblies and attached structural half-columns together bringing the inner faces of the opposing hub assemblies into contact with one another.

Abstract: An improvement of a precision manipulator for use in UHV systems with sample transfer capability in which a spring loaded thermocouple 47 and a heater electrode (51, 52) are both in direct contact with the transferred sample 35. The thermocouple and heater electrode assembly are mounted concentric with a sample receiving block 33 on the end of an offset manipulator 20. Hence, when a sample is transferred from an introduction chamber 12 into the UHV chamber 11, it contacts the spring loaded thermocouple 47 and then seats a heater electrode 52. Cooling by a copper plate 41 and a strap 22 combined with the resistance heating capability allow sample temperatures over the range of 150.degree.-1750.degree. K. while positioned in front of any diagnostic instrument in the UHV system and while taking data with these instruments.

Abstract: A noninvasive accurate method for measuring the temperature of tissue beneath the surface of a living body 11. Ultrasonic signals (14) are directed into beads 13 of a material that are inserted into the tissue with a syringe. The reflected signals (15) indicate the acoustic impedance or resonance frequency of the beads 13 which in turn indicates the temperature of the tissue. A range of temperatures around the melting temperature of the material can be measured by this method.

Abstract: A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces have line element extensions that pass through a common point.