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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,441 records · Page 80

All sources NASA NTRS DOE OSTI

NASA NTRS1991

Fast-Acting Rubber-To-Coated-Aluminum Adhesive

Cyanoacrylate adhesive used to join rubber to coated aluminum easier to apply and more effective. One-part material applied in single coat to aluminum treated previously with epoxy primer and top coat. Parts mated as soon as adhesive applied; no drying necessary. Sets in 5 minutes. Optionally, accelerator brushed onto aluminum to reduce setting time to 30 seconds. Clamping parts together unnecessary. Adhesive comes in four formulations, all based on ethyl cyanoacrylate with various amounts of ethylene copolymer rubber, poly(methyl methacrylate), silicon dioxide, hydroquinone, and phthalic anhydride.

Comer, Dawn A.↗

NASA NTRS1991

Making Three-Layer Solid Electrolyte/Electrode Sandwiches

Tape-casting-and-sintering process joins two ceramic materials having widely different sintering temperatures into integral sandwich structure. Layers retain their identities, without migration of constituents. Used to make three-layer structure composed of outer porous layers of strontium-doped lanthanum manganite and inner dense layer of yttria-stabilized zirconia. Structures used to make electrolytic and fuels cells with solid electrolytes for use at high temperatures. Other potential applications include oxygen pumps and oxygen sensors.

Schroeder, James E.↗

NASA NTRS1991

Damping Of Vibrations In Graphite/Epoxy Structures

Report describes study of vibration-damping properties, in air and vacuum, of graphite/epoxy composite structural members joined by adhesives. Determines vibration-damping effects of specimens representative of members and joints of truss, particularly after gases and moisture trapped during manufacture released in vacuum. Damping ratios measured under free and forced vibrations and before and after outgassing in vacuum. Effects of end-support conditions and high and low temperatures on damping also measured.

Crocker, Malcolm J.↗

NASA NTRS1991

Docking System Would Accommodate Misalignments

Conceptual docking system absorbs kinetic energy along each of three orthogonal directions. Accommodates large misalignments between docking objects. Lightweight system consists of probe on one of two docking objects and drogue on other object. Probe contains latching mechanism; pitch, roll, and yaw dampers; and centering and rigidizing mechanisms. Three eddy-current dampers absorb energy of motion along orthogonal directions, bringing docking objects to smooth stop. Conceived for docking Space Shuttle in Space Station, system useful in other applications in which large moving object must be aligned with and joined to another - such as, cranes, robots, and fuel or material-loading lines.

Ajemian, Rasmik↗

NASA NTRS1991

Heat-Transfer Coupling For Heat Pipes

Proposed welded heat-transfer coupling joins set of heat pipes to thermoelectric converter. Design avoids difficult brazing operation. Includes pair of mating flanged cups. Upper cup integral part of housing of thermoelectric converter, while lower cup integral part of plate supporting filled heat pipes. Heat pipes prefilled. Heat of welding applied around periphery of coupling, far enough from heat pipes so it would not degrade working fluid or create excessive vapor pressure in the pipes.

Nesmith, Bill J.↗

NASA NTRS1991

Trailing Shield For Welding On Pipes

Trailing shield ensures layer of inert gas covers hot, newly formed bead between two tubes or pipes joined by plasma arc welding. Inert gas protects weld bead from oxidation by air until cooler and less vulnerable to oxidation. Intended for use on nickel-base alloy pipes, on which weld beads remain hot enough to oxidize after primary inert-gas purge from welding-torch cup has passed.

Coby, John B., Jr.↗

NASA NTRS1990

Heat transfer device and method of making the same

Gas derived graphite fibers are generated by the decomposition of an organic gas. These fibers when joined with a suitable binder are used to make a high thermal conductivity composite material. The fibers may be intercalated. The intercalate can be halogen or halide salt, alkaline metal, or any other species which contributes to the electrical conductivity improvement of the graphite fiber. The heat transfer device may also be made of intercalated highly oriented pyrolytic graphite and machined, rather than made of fibers.

Banks, Bruce A.↗

NASA NTRS1990

Mechanical end joint system for connecting structural column elements

A mechanical end joint system is presented that eliminates the possibility of free movements between the joint halves during loading or vibration. Both node joint body (NJB) and column end joint body (CEJB) have cylindrical engaging ends. Each of these ends has an integral semicircular tongue and groove. The two joint halves are engaged transversely - the tongue of the NJB mating with the groove of the CEJB and vice versa. The joint system employs a spring loaded internal latch mechanism housed in the CEJB. During mating, this mechanism is pushed away from the NJB and enters the NJB when mating is completed. In order to lock the joint and add a preload across the tongue and groove faces, an operating ring collar is rotated through 45 deg causing an internal mechanism to compress a Belleville washer preload mechanism. This causes an equal and opposite force to be exerted on the latch bolt and the latch plunger. This force presses the two joint halves tightly together. In order to prevent inadvertent disassembly, a secondary lock is also engaged when the joint is closed. Plungers are carried in the operating ring collar. When the joint is closed, the plungers fall into tracks on the CEJB, which allows the joint to be opened only when the operating ring collar and plungers are pushed directly away from the joining end. One application of this invention is the rapid assembly and disassembly of diverse skeletal framework structures which is extremely important in many projects involving the exploration of space.

Bush, Harold G.↗

NASA NTRS1990

Processable polyimide adhesive and matrix composite resin

A high temperature polyimide composition prepared by reacting 4,4'-isophthaloyldiphthalic anhydride with metaphenylenediamine is employed to prepare matrix resins, adhesives, films, coatings, moldings, and laminates, especially those showing enhanced flow with retention of mechanical and adhesive properties. It can be used in the aerospace industry, for example, in joining metals to metals or metals to composite structures. One area of application is in the manufacture of lighter and stronger aircraft and spacecraft structures.

Pratt, J. Richard↗

NASA NTRS1990

Compliant joint

A compliant joint is provided for prosthetic and robotic devices which permits rotation in three different planes. The joint provides for the controlled use of cable under motion. Perpendicular outer mounting frames are joined by swaged cables that interlock at a center block. Ball bearings allow for the free rotation of the second mounting frame relative to the first mounting frame within a predetermined angular rotation that is controlled by two stop devices. The cables allow for compliance at the stops and the cables allow for compliance in six degrees of freedom enabling the duplication or simulation of the rotational movement and flexibility of a natural hip or knee joint, as well as the simulation of a joint designed for a specific robotic component for predetermined design parameters.

Eklund, Wayne D.↗

NASA NTRS1990

High altitude reconnaissance aircraft

At the equator the ozone layer ranges from 65,000 to 130,000 plus feet, which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 feet for six hours at Mach 0.7, while carrying 3,000 lbs. of payload. In addition, the aircraft must have a minimum range of 6,000 miles. In consideration of the novel nature of this project, the pilot must be able to take control in the event of unforeseen difficulties. Three aircraft configurations were determined to be the most suitable - a joined-wing, a biplane, and a twin-boom conventional airplane. The performance of each configuration was analyzed to investigate the feasibility of the project.

Yazdo, Renee Anna↗

NASA NTRS1991

Plasma contactor research, 1990

Emissive and Langmuir probes were used to measure plasma potential profiles, plasma densities, electron energy distributions, and plasma noise levels near a hollow cathode-based plasma contactor emitting electrons. The effects of electron emission current (100 to 1500 mA) and contactor flowrate (2 to 10 sccm (Xenon)) on these data are examined. Retarding potential analyzer (RPA) measurements showing that high energy ions generally stream from a contactor along with the electrons being emitted are also presented, and a mechanism by which this occurs is postulated. This mechanism, which involves a high rate of ionization induced between electrons and atoms flowing together from the hollow cathode orifice, results in a region of high positive space charge and high positive potential. Langmuir and RPA probe data suggests that both electrons and ions expand spherically from this potential hill region. In addition to experimental observations, a simple one-dimensional model which describes the electron emission process and predicts the phenomena just mentioned is presented and is shown to agree qualitatively with these observations. Experimental results of the first stage of bilateral cooperation with the Italian Institute of Interplanetary Space Physics (IFSI CNR) are presented. Sharp, well-defined double layers were observed downstream of a contactor collecting electrons from an ambient plasma created in the IFSI Facility. The voltage drop across these double layers was observed to increase with the current drawn from the ambient plasma. This observation, which was not as clear in previous IFSI tests conducted at higher neutral pressures, is in agreement with previous experimental observations made at both Colorado State University and NASA Lewis Research Center. Greater double layer voltage drops, multiple double layers, and higher noise levels in the region near the double layers were also observed when a magnetic field was imposed and oriented perpendicular to the line joining the contactor and simulator.

Williams, John D.↗

NASA NTRS1990

The Combined Release and Radiation Effects Satellite (CRRES) program: A unique series of scientific experiments

The Defense Department and NASA have joined in a program to study the space environment which surrounds the earth and the effects of space radiation on modern satellite electronic systems. The Combined Release and Radiation Effects Satellite (CRRES) will carry an array of active experiments including chemical releases and a complement of sophisticated scientific instruments to accomplish these objectives. Other chemical release active experiments will be performed with sub-orbital rocket probes. The chemical releases will 'paint' the magnetic and electric fields of earthspace with clouds of glowing ions. Earthspace will be a laboratory, and the releases will be studied with an extensive network of ground-, aircraft-, and satellite-based diagnostic instruments. Some of the topics discussed include the following: the effects of earthspace; the need for active experiments; types of chemical releases; the CRRES program schedule; international support and coordinated studies; photographing chemical releases; information on locating chemical releases for observation by the amateur; and CRRES as a program.

Reasoner, David L.↗

NASA NTRS1990

NASA Space Engineering Research Center for utilization of local planetary resources

The University of Arizona and NASA have joined to form the UA/NASA Space Engineering Research Center. The purpose of the Center is to discover, characterize, extract, process, and fabricate useful products from the extraterrestrial resources available in the inner solar system (the moon, Mars, and nearby asteroids). Individual progress reports covering the center's research projects are presented and emphasis is placed on the following topics: propellant production, oxygen production, ilmenite, lunar resources, asteroid resources, Mars resources, space-based materials processing, extraterrestrial construction materials processing, resource discovery and characterization, mission planning, and resource utilization.

Ramohalli, Kumar↗

NASA NTRS1991

Braze alloy process and strength characterization studies for 18 nickel grade 200 maraging steel with application to wind tunnel models

A comprehensive study of braze alloy selection process and strength characterization with application to wind tunnel models is presented. The applications for this study include the installation of stainless steel pressure tubing in model airfoil sections make of 18 Ni 200 grade maraging steel and the joining of wing structural components by brazing. Acceptable braze alloys for these applications are identified along with process, thermal braze cycle data, and thermal management procedures. Shear specimens are used to evaluate comparative shear strength properties for the various alloys at both room and cryogenic (-300 F) temperatures and include the effects of electroless nickel plating. Nickel plating was found to significantly enhance both the wetability and strength properties for the various braze alloys studied. The data are provided for use in selecting braze alloys for use with 18 Ni grade 200 steel in the design of wind tunnel models to be tested in an ambient or cryogenic environment.

Bradshaw, James F.↗

NASA NTRS1989

End-effector-joint conjugates for robotic assembly of large truss structures in space: A second generation

Attachment of strut to node can be accomplished with a variety of mechanisms. All require extensive standoff elements (called scars) added to the nodes. These increase packaging volume for the nodes by as much as 300 percent. First generation designs also tend to be either heavy or expensive due to complex parts. Screws thread mechanisms are discussed simplest and most easily manufactured of alternatives. Torque and rotational motion must be transmitted across the strut to end-effector interface accomplishing the joining process and establishing a specific preload. Four drive mechanisms are considered: worm, helical, bevel, and differential gears.

Brewer, William V.↗

NASA NTRS1991

Apparatus and method for explosive bonding to edge of flyer plate

The invention is an apparatus and a process for the explosive joining of a flyer plate and a base plate. The apparatus consists of a flyer plate positioned over a base plate. The flyer plate has a notch containing a filler material in intimate contact with the flyer plate. An adhesive means holds a ribbon explosive partially overlapping the notch in the flyer plate. A detonating means initiates the ribbon explosive that drives the flyer plate to accomplish a high velocity, angular collision between the mating surfaces. This collision creates surface melts and effacing bonding, resulting in electron sharing linkups between the plates. An unbonded tab fractures at a base of the notch leaving a bond to an edge of the attached flyer plate.

Bement, Laurence J.↗

NASA NTRS1991

Two fault tolerant toggle-hook release

A coupling device is disclosed which is mechanically two fault tolerant for release. The device comprises a fastener plate and fastener body, each of which is attachable to a different one of a pair of structures to be joined. The fastener plate and body are coupled by an elongate toggle mounted at one end in a socket on the fastener plate for universal pivotal movement thereon. The other end of the toggle is received in an opening in the fastener body and adapted for limited pivotal movement therein. The toggle is adapted to be restrained by three latch hooks arranged in symmetrical equiangular spacing about the axis of the toggle, each hook being mounted on the fastener body for pivotal movement between an unlatching non-contact position with respect to the toggle and a latching position in engagement with a latching surface of the toggle. The device includes releasable lock means for locking each latch hook in its latching position whereby the toggle couples the fastener plate to the fastener body and means for releasing the lock means to unlock each said latch hook from the latch position whereby the unlocking of at least one of the latch hooks from its latching position results in the decoupling of the fastener plate from the fastener body.

Graves, Thomas Joseph↗