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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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Microwave radiometric observations of simulated sea surface conditions.

Review of the results of an experimental investigation of various factors affecting the surface properties of the ocean as seen by a passive microwave radiometer operating at 2.66 GHz. The principal uncertainties in the absolute measurements of the thermal emissions from the sea in terms of molecular temperature are shown to stem from (1) surface contaminations, such as oil slicks, (2) spray and foam, (3) salinity variation, and (4) surface waves. The results of a variety of experiments conducted so far indicate that the direct contribution of surface films and spray to the thermal emission from the sea is considerably less significant than that of foam and waves.

Van Melle, M. J.↗
NASA NTRS1973

Erosion of polyurethane insulation.

Detailed description of the test program in which erosion of the spray foam insulation used in the S-II stage of the Saturn-V Apollo launch vehicle was investigated. The behavior of the spray foam was investigated at the elevated temperature and static pressure appropriate to the S-II stage environment, but in the absence of the aerodynamic shear stress.

Kraus, S.↗
NASA NTRS1974

Inexpensive lightweight mirror

Aluminized Mylar film is bonded to polyurethane foam mold; Mylar is then removed, leaving highly reflective coating of aluminum on foam. Mold may be used repeatedly to make mirrors for several optical instruments. Large mirrors of almost any shape may be made singularly or in quantity.

Badhwar, G. D.↗
NASA NTRS1975

Space processing of composite materials

Materials and processes for the testing of aluminum-base fiber and particle composites, and of metal foams under extended-time low-g conditions were investigated. A wetting and dispersion technique was developed, based on the theory that under the absence of a gas phase all solids are wetted by liquids. The process is characterized by a high vacuum environment and a high temperature cycle. Successful wetting and dispersion experiments were carried out with sapphire fibers, whiskers and particles, and with fibers of silicon carbide, pyrolytic graphite and tungsten. The developed process and facilities permit the preparation of a precomposite which serves as sample material for flight experiments. Low-g processing consists then merely in the uniform redistribution of the reinforcements during a melting cycle. For the preparation of metal foams, gas generation by means of a thermally decomposing compound was found most adaptable to flight experiments. For flight experiments, the use of compacted mixture of the component materials limits low-g processing to a simple melt cycle.

Steurer, W. H.↗
NASA NTRS1975

Flame resistant elastomeric polymer development

Elastomeric products were developed for use in the space shuttle program, and investigations were conducted to improve the properties of elastomers developed in previous programs, and to evaluate the possibility of using lower-cost general purpose polymers. Products were fabricated and processed on conventional processing equipment; these products include: foams based on fluorinated rubber flame-retarded compounds with a density of 20-30 pounds/cubic foot for use as padding and in helmets; foams based on urethane for use in instrument packaging in the space shuttle; flexible and semi-rigid films of fluorinated rubber and neoprene compounds that would not burn in a 70% nitrogen, 30% oxygen atmosphere, and in a 30% nitrogen, 70% oxygen atmosphere, respectively for use in packaging or in laminates; coated fabrics which used both nylon and Kelvar fabric substrates, coated with either fluorinated or neoprene polymer compositions to meet specific levels of flame retardancy; and other flame-resistant materials.

Howarth, J. T.↗
NASA NTRS1975

Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 1

The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacture of large helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D helicopter was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR-49/epoxy skin and graphite/epoxy frames and stringers. To support the selection of this specific design concept a materials study was conducted to develop and select a cure compatible graphite and KEVLAR-49/epoxy resin system, and a foam system capable of maintaining shape and integrity under the processing conditions established. The materials selected were, Narmco 5209/Thornel T-300 graphite, Narmco 5209/KEVLAR-49 woven fabric, and Stathane 8747 polyurethane foam. Eight specimens were fabricated, representative of the frame, stringer, and splice joint attachments. Evaluation of the results of analysis and test indicate that design predictions are good to excellent except for some conservatism of the complex frame splice.

Adams, K. M.↗
NASA NTRS1975

Ablative overlays for Space Shuttle leading edge ascent heat protection

Ablative overlays were evaluated via a plasma-arc simulation of the ascent pulse on the leading edge of the Space Shuttle Orbiter. Overlay concepts included corkboard, polyisocyanurate foam, low-density Teflon, epoxy, and subliming salts. Their densities ranged from 4.9 to 81 lb per cu ft, and the thicknesses varied from 0.107 to 0.330 in. Swept-leading-edge models were fabricated from 30-lb per cu ft silicone-based ablators. The overlays were bonded to maintain the surface temperature of the base ablator below 500 F during ascent. Foams provided minimum-weight overlays, and subliming salts provided minimum-thickness overlays. Teflon left the most uniform surface after ascent heating.

Strauss, E. L.↗
NASA NTRS1975

Experimental verification of turbulent skin friction reduction with compliant walls

Preliminary compliant wall skin friction test results obtained in a low-turbulence pressure tunnel are reported. Compliant surface skins consisted of 0.0025 cm thick mylar, stretched under tension and area-bonded or longitudinally strip-bonded with silicone rubber adhesive to polyurethane foam. Mean velocity and fluctuating survey data were obtained with a single slanted hot wire. Mean velocity profiles for the area-bonded mylar surface skins indicated up to a 20% reduction in boundary-layer thickness (and lower momentum thickness) over rigid surfaces. This reduction in boundary-layer thickness indicates that a drag reduction occurred. In addition, a 16% reduction in wall shear was evident for the mylar/compressor foam compliant surface.

Weinstein, L. M.↗
NASA NTRS1977

Uniform spray coating for large tanks

System employs spray facility located within ventilated plastic booth to uniformly coat exterior of large cylindrical tanks with polyurethane foam insulation. Coating target is rotated on turntable while movable spray guns apply overlapping spirals of foam. Entire operation may be controlled by single operator from remote station.

Carter, J. M.↗
NASA NTRS1977

Development of fire-resistant, low smoke generating, thermally stable end items for aircraft and spacecraft

Materials were developed to improve aircraft interior materials by modifying existing polymer structures, refining the process parameters, and by the use of mechanical configurations designed to overcome specific deficiencies. The optimization, selection, and fabrication of five fire resistant, low smoke emitting open cell foams are described for five different types of aircraft cabin structures. These include: resilient foams, laminate floor and wall paneling, thermal/acoustical insulation, molded shapes, and coated fabrics. All five have been produced from essentially the same polyimide precursor and have resulted in significant benefits from transfer of technology between the various tasks.

Gagliani, J.↗
NASA NTRS1976

You can't eat moon rocks

The effects produced by the aerospace program are investigated. The technology developed from aerospace-related research, development, and manufacturing has been made available to the public for its use through the NASA Technology Utilization Program. A description is presented of 'spinoffs' of NASA's aerospace programs which are used on a daily basis by the public. Attention is given to the liquid cooled garment technology, meal systems for the elderly, the zinc-rich coating, the emergency blanket, the flexible urethane foam Temper Foam, the 'Fog-Away Coating', and composite graphite equipment.

Kubokawa, C. C.↗
NASA NTRS1979

Insulator for cryogenic joints

Semirigid polyurethane foam is firm enough not to collapse yet soft enough not to crack in extreme cold. Silicone cover retards flames and glass-fabric reinforcement protects foam against accidental damage from tools during installation and maintenance.

Hawkinson, E. L.↗
NASA NTRS1977

Spacecraft disinfectant/cleansing agent development

The sanitation agent container, which was selected in a trade off study, employs two chambers, a rigid outer container and an inner flexible bladder. The bladder contains the sanitation agent formulation and its release is controlled by a manually operated valve. The outer container holds a high pressure vapor. There is no void in the bladder which makes the package operation independent of orientation and therefore usable in zero gravity. Foam is developed by a low boiling point fluid or dissolved in the product. When the product is dispensed at atmospheric presure, the evolved gas or vapor whips up a goam in the valve. The sanitation agents were initially formulated with freons which produces an excellent foam. However freon is incompatible with the life support system and was replaced with carbon dioxide dissolved at high pressure. The CO2 system may limit high temperature exposure to prevent leakage or package distortion. The sanitation agents have been shown to be effective in cleaning soils from personnel and material.

Abbate, M.↗
NASA NTRS1978

Fabrics for fire resistant passenger seats in aircraft

The essential elements of the problem and of approaches to improved fire resistance in aircraft seats are reviewed. The performance requirements and availability of materials, delay in the ignition of upholstery fabric by a small source are considered a realistic objective. Results of experimental studies on the thermal response of fabrics and fabric/foam combinations suggest significant conclusions regarding: (1) the ignition behavior of a commercial 90/10 wool/nylon upholstery fabric relative to fabrics made from thermally stable polymers; (2) the role of the foam backing; (3) the behavior of seams. These results, coupled with data from other sources, also confirm the importance of materials' interactions in multicomponent assemblies, and the need for system testing prior to materials' selection. The use of an interlinear or thermal barrier between upholstery fabric and foam is a promising and viable approach to improved fire resistance of the seat assembly, but experimental evaluation of specific combinations of materials or systems is an essential part of the selection process.

Tesoro, G. C.↗
NASA NTRS1979

Release-rate calorimetry of multilayered materials for aircraft seats

Multilayered samples of contemporary and improved fire resistant aircraft seat materials (foam cushion, decorative fabric, slip sheet, fire blocking layer, and cushion reinforcement layer) were evaluated for their rates of heat release and smoke generation. Top layers (decorative fabric, slip sheet, fire blocking, and cushion reinforcement) with glass fiber block cushion were evaluated to determine which materials based on their minimum contributions to the total heat release of the multilayered assembly may be added or deleted. Top layers exhibiting desirable burning profiles were combined with foam cushion materials. The smoke and heat release rates of multilayered seat materials were then measured at heat fluxes of 1.5 and 3.5 W/sq cm. Choices of contact and silicone adhesives for bonding multilayered assemblies were based on flammability, burn and smoke generation, animal toxicity tests, and thermal gravimetric analysis. Abrasion tests were conducted on the decorative fabric covering and slip sheet to ascertain service life and compatibility of layers.

Fewell, L. L.↗
NASA NTRS1980

Flush-mounting technique for composite beams

Procedure permits mounting of heavy parts to surface of composite beams without appreciably weakening beam web. Web is split and held apart in region where attachment is to be made by lightweight precast foam filler. Bolt hole penetrates foam rather than web, and is secured by barrelnut in transverse bushing through web.

Harman, T. C.↗
NASA NTRS1980

Release-rate calorimetry of multilayered materials for aircraft seats

Multilayered samples of contemporary and improved fire-resistant aircraft seat materials (foam cushion, decorative fabric, slip sheet, fire-blocking layer, and cushion-reinforcement layer) were evaluated for their rates of heat release and smoke generation. Top layers (decorative fabric, slip sheet, fire blocking, and cushion reinforcement) with glass-fiber block cushion were evaluated to determine which materials, based on their minimum contributions to the total heat release of the multilayered assembly, may be added or deleted. Top layers exhibiting desirable burning profiles were combined with foam cushion materials. The smoke and heat-release rate of multilayered seat materials were then measured at heat fluxes of 1.5 and 3.5 W/sq cm. Choices of contact and silicon adhesives for bonding multilayered assemblies were based on flammability, burn and smoke generation, animal toxicity tests, and thermal gravimetric analysis.

Fewell, L. L.↗