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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 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Gear materials for high-production light-deputy service

The selection of a material for high volume, low cost gears requires careful consideration of all the requirements and the processes used to manufacture the gears. The wrong choice in material selection could very well mean the difference between success and failure. A summary of the cost that might be expected for different materials and processes is presented; it can be seen that the cost can span nearly three order of magnitudes from the molded plastic gear to the machined gear with stamped and powder metal gears falling in between these extremes.

Townsend, D. P.↗
NASA NTRS1973

Silica Reusable Surface Insulation Improvement Research

Fiber characterization, fabrication processes, physical properties, and thermal responses are investigated to improve silica reusable surface insulation tiles. Criteria for fiber selection on the basis of chemical composition, shrinkage, and devitrification have been defined and a simple process for fabricating silica surface insulation materials has been developed that produces only 5% shrinkage and no devitrification of tiles at 1533 K in ten hours. Anisotropic tile with improved weak direction strength has been fabricated using conventional molding techniques.

Goldstein, H. E.↗
NASA NTRS1973

Development of the Astrobee F sounding rocket system.

The development of the Astrobee F sounding rocket vehicle through the first flight test at NASA-Wallops Station is described. Design and development of a 15 in. diameter, dual thrust, solid propellant motor demonstrating several new technology features provided the basis for the flight vehicle. The 'F' motor test program described demonstrated the following advanced propulsion technology: tandem dual grain configuration, low burning rate HTPB case-bonded propellant, and molded plastic nozzle. The resultant motor integrated into a flight vehicle was successfully flown with extensive diagnostic instrumentation.-

Jenkins, R. B.↗
NASA NTRS1973

High temperature resistant composites from bismaleimide resin.

It is shown that bismaleimide/woven fiberglass composites molded at moderate pressures (100 psi) yield void-free laminates of good integrity. The strength of the laminates at room temperature compares favorably with epoxy/glass laminates; at 260 C, the laminates are far superior in oxidative aging to epoxy and silicon laminates. The synthesis, processing, and fabrication of a bismaleide polymer are discussed.

Gilwee, W. J.↗
NASA NTRS1973

Initial development of an ablative leading edge for the Space Shuttle orbiter.

A state-of-the-art preliminary design for typical wing areas is developed. Seven medium-density ablators (with/without honeycomb, flown on Apollo, Prime, X15A2) are evaluated. The screening tests include (1) leading-edge models sequentially subjected to ascent heating, cold soak, entry heating, post-entry pressure fluctuations, and touchdown shock, and (2) virgin/charred models subjected to bondline strains. Four materials (none molded) are found acceptable. The ESA 3560 HF and MOD 7 Hc (an AVCO 30 pcf elastomer) are selected. Roughness/recession degradation of low speed aerodynamics appears acceptable. The design, including attachments, substructure and joints, is presented.

Daforno, G.↗
NASA NTRS1973

Evaluation of proposed Skylab and SSP soap products.

Four candidate cleansing agents evaluated in terms of potential hazards to crew members included two soaps (Neutrogena bar soap and Olive Leaf Liquid), one nonfoaming surfactant (Miranol JEM), and one laundry detergent (sodium dodecylbenzene sulfonate). None of the four exhibited adverse dermatological effects from skin patch tests or supported growth of potentially pathogenic microorganisms. Aqueous solutions of Neutrogena did support a mold species. Neutrogena and Miranol JEM were used in a simulated Skylab personal hygiene regimen with no adverse effects on skin or skin microflora. Based on our results, each of these agents appear to be a promising candidate material for the use intended.

Durfee, R. L.↗
NASA NTRS1974

Cushion module for stowing electronic equipment

To provide vibration-resistance composition adjust processing techniques, which produces essentially void-free materials and provides for clean removal of finished material from mold. Microsphere filler imparts strength to polymer and sodium carbonate imparts flame-resistance.

Rogers, J. R.↗
NASA NTRS1973

Investigation of low-cost fabrication of ablative heat shields

The fabrication, testing, and evaluation of materials and techniques employed in the fabrication of ablative heat shield panels are described. Results of this effort show projected reductions in labor man-hours for dielectric curing of panels when compared to panels molded in a steam-heated press. In addition, panels were fabricated with more than one density within the cross-section. These dual-density panels show significant weight and cost reduction potentials.

Massions, V. P.↗
NASA NTRS1973

HNS/Teflon, a new heat resistant explosive

HNS/Teflon (90/10) is a new pressed explosive developed for use in the Apollo program. The major advantages of HNS/Teflon are (1) excellent thermal stability at elevated temperatures, (2) superior resistance to sublimation at high temperatures and low pressures and (3) ease of molding powder preparation, pressing and machining. The impact sensitivity of HNS/Teflon is between that of Comp B and Comp A-3 while its explosive performance is about the same as TNT. Under the severe environmental conditions of the moon's surface, this explosive successfully performed its intended function of generating seismic waves in the Apollo ALSEP and LSPE experiments. (Modified author abstract)

Heller, H.↗
NASA NTRS1974

The thermal and mechanical properties of a low-density glass-fiber-reinforced elastomeric ablation material

An evaluation of the thermal and mechanical properties was performed on a molded low-density elastomeric ablation material designated as Material B. Both the virgin and charred states were examined to provide meaningful inputs to the design of a thermal protection system. Chars representative of the flight chars formed during ablation were prepared in a laboratory furnace from 600 K to 1700 K and properties of effective thermal conductivity, heat capacity, porosity and permeability were determined on the furnace chars formed at various temperature levels within the range. This provided a boxing of the data which will enable the prediction of the transient response of the material during flight ablation.

Engelke, W. T.↗
NASA NTRS1974

Material cutting, shaping, and forming: A compilation

Information is presented concerning cutting, shaping, and forming of materials, and the equipment and techniques required for utilizing these materials. The use of molds, electrical fields, and mechanical devices are related to forming materials. Material cutting methods by devices including borers and slicers are presented along with chemical techniques. Shaping and fabrication techniques are described for tubing, honeycomb panels, and ceramic structures. The characteristics of the materials are described. Patent information is included.

Source record↗
NASA NTRS1974

Method of laminating structural members

A laminate is obtained by providing a lightweight core material, such as a honeycombed plastic or metal, within the cavity defined by an annular mold cavity frame. Face sheets, which are to be bonded to the core material, are provided on opposite sides of the frame and extend over the frame, thus sealing the core material in the cavity. An adhesive is provided between the core material and the face sheets and the combined thickness of the core material and adhesive is a close fit within the opposed face sheets. A gas tight seal, such as an O-ring gasket, is provided between the frame and the face sheet members to form a gas tight cavity between the face sheet members and the frame. External heat and pressure are used to bond the face sheets to the core material. Gas pressure is introduced into the sealed cavity to minimize out-gasing of the adhesive.

Heier, W. C.↗
NASA NTRS1972

The Myxomycetes

The classification, life cycle, morphology, and physiology of the class Myxomycetes (slime molds) are reported. Myoxomytes culture, maintenance, and storage are discussed.

Koppel, H.↗
NASA NTRS1974

Topography of aortic heart valves

The cooperative effort towards the development of a tri-leaflet prosthetic heart valve is described. The photogrammetric studies were conducted on silicone rubber molds. Information on data acquisition and data reduction phases is given, and certain accuracy aspects of the project are explained. The various outputs which are discussed include digital models, profiles, and contour maps.

Karara, H. M.↗
NASA NTRS1974

Method of applying a mirror reflecting layer to instrument parts

A method follows for applying a mirror reflecting layer to the surfaces of parts, instruments, apparatus, and so on. A brief analysis is presented of the existing methods of obtaining the mirror surface and the advantages of the new method of obtaining the mirror surface by polymer casting mold are indicated.

Alkhanov, L. G.↗
NASA NTRS1974

Friction and friction-generated temperature at a polymer-metal interface

Results of friction and thermal tests of molded polyimide and pyrrone polymers are presented. The coefficient of sliding friction up to surface velocities of 2 m/sec and the coefficient of thermal expansion from 300 to 500 K were measured. An apparatus was constructed to measure simultaneously the coefficient of sliding friction and the friction-generated temperature. Measurements were made at a nominal pressure-velocity product of 0.25 MN/msec and at temperatures between 300 and 500 K.

Price, H. L.↗
NASA NTRS1974

Polyimide resin composites via in situ polymerization of monomeric reactants

Thermo-oxidatively stable polyimide/graphite-fiber composites were prepared using a unique in situ polymerization of monomeric reactants directly on reinforcing fibers. This was accomplished by using an aromatic diamine and two ester-acids in a methyl alcohol solvent, rather than a previously synthesized prepolymer varnish, as with other A-type polyimides. A die molding procedure was developed and a composite property characterization conducted with high modulus graphite fiber tow. Flexure, tensile, compressive, and shear tests were conducted at temperatures from 72 to 650 F on laminates before and after exposures at the given temperatures in an air environment for times up to 1000 hours. The composite material was determined to be oxidatively, thermally, and hydrolytically stable.

Cavano, P. J.↗
NASA NTRS1974

Application of advanced composites to helicopter airframe structures

The present work outlines a study whose objective was to assess the possible use of advanced composite materials to helicopter fuselage structure. The study used the CH-53D as a baseline design for comparison of composite with current conventional construction. Boron/epoxy and graphite/epoxy appeared to be the prime candidate materials for the major portion of the primary structure, while Kevlar-49/epoxy was the prime candidate material for secondary structure. A single-laminate shear-carrying skin combined with stringers and frames in an all-molded construction was considered the most promising concept for the airframe shell construction; foam-stabilized graphite/epoxy stringer was considered the prime concept for stringer construction. Shell construction and assembly concepts are discussed, and comparison of weight and material between current CH-53D airframe and the composite airframe shows that the latter may represent an 18% weight saving. Based on a fleet requirement of 600 vehicles, the operating cost for a fleet of helicopters constructed with the composite material airframe flying 500 hours a year per aircraft over a ten-year service life was calculated, indicating a $337,000 saving per helicopter.

Rich, M. J.↗