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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Energy management and recovery

Energy management is treated by first exploring the energy requirements for a cryogenic tunnel. The requirement is defined as a function of Mach number, Reynolds number, temperature, and tunnel size. A simple program and correlation is described which allow calculation of the energy required. Usage of energy is also addressed in terms of tunnel control and research operation. The potential of a new wet expander is outlined in terms of cost saved by reliquefying a portion of the exhaust. The expander is described as a potentially more efficient way of recovering a fraction of the cold nitrogen gas normally exhausted to the atmosphere from a cryogenic tunnel. The role of tunnel insulation systems is explored in terms of requirements, safety, cost, maintenance, and efficiency. A detailed description of two external insulation systems is given. One is a rigid foam with a fiber glass and epoxy shell. The other is composed of glass fiber mats with a flexible outer vapor barrier; this system is nitrogen purged. The two systems are compared with the purged system being judged superior.

Lawing, Pierce L.↗
NASA NTRS1993

Production of Lunar Concrete Using Molten Sulfur

The United States has made a commitment to go back to the moon to stay in the early part of the next century. In order to achieve this objective it became evident to NASA that a Lunar Outpost will be needed to house scientists and astronauts who will be living on the moon for extended periods of time. A study has been undertaken by the authors and supported by NASA to study the feasibility of using lunar regolith with different binders such as molten sulfur, epoxy or hydraulic cement as a construction material for different lunar structures. The basic premise of this study is that it will be more logical and cost effective to manufacture lunar construction materials utilizing indigenous resources rather than transporting needed materials from earth. Lunar concrete (made from Hydraulic Cement and lunar soil) has been studied and suggested as the construction material of choice for some of the lunar projects. Unfortunately, its hydration requires water which is going to be a precious commodity on the moon. Therefore this study explores the feasibility of using binders other than hydraulic cement such as sulfur or epoxy with lunar regolith as a construction material. This report describes findings of this study which deals specifically with using molten sulfur as a binder for Lunar concrete. It describes laboratory experiments in which the sulfur to lunar soil simulant ratios by weight were varied to study the minimum amount of sulfur required to produce a particular strength. The compressive and tensile strengths of these mixes were evaluated. Metal and fiber glass fibers were added to some of the mixes to study their effects on the compressive and tensile strengths. This report also describes experiments where the sulfur is melted and mixed with the lunar regolith in a specially designed vacuum chamber. The properties of the produced concrete were compared to those of concrete produced under normal pressure.

Omar, Husam A.↗
NASA NTRS1978

Glass matrix composites. I - Graphite fiber reinforced glass

An experimental program is described in which graphite fibers of Hercules HMS and HTS, Thornel 300, and Celanese DG-12 were used to reinforce, both uniaxially and biaxially, borosilicate pyrex glass. Composite flexural strength distribution, strength as a function of test temperature, fracture toughness and oxidative stability were determined and shown to be primarily a function of fiber type and the quality of fiber-matrix bond formed during composite fabrication. It is demonstrated that the graphite fiber reinforced glass system offers unique possibilities as a high performance structural material.

Prewo, K. M.↗
NASA NTRS1980

Safely splicing glass optical fibers

Field-repair technique fuses glass fibers in flammable environment. Apparatus consists of v-groove vacuum chucks on manipulators, high-voltage dc power supply and tungsten electrodes, microscope to observe joint alignment and fusion, means of test transmission through joint. Apparatus is enclosed in gas tight bos filled with inert gas during fusion. About 2 feet of fiber end are necessary for splicing.

Korbelak, K.↗
NASA NTRS2000

Indicator Devices for Detection of Trace Gaseous Hydrazines

The relatively recent decrease in the acceptable time-weighted-average for hydrazines from 100 parts-per-billion (ppb) to 10 ppb rendered many trace hydrazine detectors either insensitive or inaccurate. Development of a rapid detection method for hydrazines at the new 10-ppb concentration was necessary so that test area personnel could reliably assess airborne hydrazines concentrations of a potentially contaminated area prior to entry. The reduction of Au(III) to Au(0) by hydrazines is a well characterized reaction and application of the corresponding yellow to purple color change was selected as a potentially useful means for detection of trace hydrazines in air. Tests with small quantities of KAuCl4 deposited on a variety of substrates were conducted using verified sources of 1,1-dimethylhydrazine, methylhydrazine, and hydrazine at approximately 10 ppb in air. Substrates tested were glass fiber filter paper, glass beads, anion exchange resin (AuCl4- form), and diatomaceous earth. The most successful of these substrates were glass fiber filter paper and diatomaceous earth. The KAuC14 impregnated glass fiber filter paper appeared to be somewhat light sensitive so further tests were conducted using the diatomaceous earth substrate. KAuCl4 concentration, substrate particle size, and sampler configuration were evaluated. Based on these tests, the device selected for further evaluation was a 5mm OD by 50mm glass tube containing 0.02-0.03g of 45/60 mesh diatomaceous earth coated with 2 percent KAuCl4. When connected to a sampling pump, response of the device to changes in relative humidity, ambient light, and high levels of other fluids, which might also be found in a propellant test area, was evaluated. False positive responses were not detected for exposures to relative humidity changes from 10 to 80 percent, sunlight for greater than 10 minutes, or percent levels of ammonia, isopropyl alcohol, nitrogen dioxide, and hydrogen. In addition, body emissions did not produce a false positive response in view of potential application for use inside protective clothing. The device was shown to reliably detect less than 10 ppb of the hydrazines tested using a 10 to 20L sample followed by a 2 to 5 minute color development time. Some field tests were conducted in parallel with conventional acidic firebrick sorbent tubes. There was generally very good agreement between the devices and firebrick sorbent tubes when greater than 10 ppb of a hydrazine was present.

Dee, Lou A.↗
NASA NTRS1979

Graphite fiber reinforced glass matrix composites for aerospace applications

The graphite fiber reinforced glass matrix composite system is described. Although this composite is not yet a mature material, it possesses low density, attractive mechanical properties at elevated temperatures, and good environmental stability. Properties are reported for a borosilicate glass matrix unidirectionally reinforced with 60 volume percent HMS graphite fiber. The flexural strength and fatigue characteristics at room and elevated temperature, resistance to thermal cycling and continuous high temperature oxidation, and thermal expansion characteristics of the composite are reported. The properties of this new composite are compared to those of advanced resin and metal matrix composites showing that graphite fiber reinforced glass matrix composites are attractive for aerospace applications.

Prewo, K. M.↗
DOE OSTI2025

Evaluation of desiccation cracking characteristics of inorganic micro-fiber-reinforced engineered barrier material (IMEBM) for geological repository

Abstract Buffer material is crucial for the engineering barrier system to dispose of high-level radioactive waste in a geological repository. A reliable buffer material should be able to maintain good sealing characteristics and minimize desiccation cracking. In this study, the effectiveness of inorganic fiber-reinforced engineering barrier material in reducing desiccation cracks in bentonite was evaluated via desiccation tests, image analysis, and air permeability tests. The effects of fiber type (E-glass fiber and basalt fiber) and fiber content (0.0%, 0.5%, 1.0%, 1.5%, 3.0%, and 5.0% of dry weight of the bentonite) on the development of desiccation cracks in the fiber–bentonite mixtures with the same given initial moisture content were evaluated. The results indicated that the addition of fibers could significantly reduce the crack size and area in bentonite during the drying. Basalt fibers showed a slightly better reinforcement effect than E-glass fibers when the fiber content was lower than 3.0%. The addition of fibers prevented the development of penetrating cracks and significantly reduced the permeability of the bentonite after drying. The permeabilities of basalt fiber- and E-glass fiber-reinforced bentonite composites with 3% reinforcement were 5.81 × 10 –11 m 2 and 7.24 × 10 –11 m 2 , respectively, which were 64 and 51 times smaller than that of pure bentonite. X-ray–CT observation of the internal structure of the samples after drying showed that the addition of fibers significantly changed the crack morphology and potentially increased the tortuosity.

Feng, Yuan↗
NASA NTRS2017

Exotic Optical Fibers and Glasses: Innovative Material Processing Opportunities in Earth's Orbit

Exotic optical fibers and glasses are the platform material for photonics applications, primarily due to their superior signal transmission (speed, low attenuation), with extending bandwidth deep into the infrared, exceeding that of silica fibers. Gravitational effects (convection sedimentation) have a direct impact on the phase diagram of these materials and influence melting properties, crystallization temperatures, and viscosity of the elemental mix during the manufacturing process. Such factors constitute limits to the yield, transmission quality, and strength and value of these fibers; they also constrain the range of applications. Manufacturing in a gravity-free environment such as the Earth’s Orbit also helps with other aspects of the fabrication process (i.e., improved form factor of the manufacturing unit, sustainability). In this article, revolutionary developments in the field of photonics over the past decade merge with the paradigm shift in the privatization of government-owned capabilities supporting a more diverse infrastructure (parabolic, suborbital, orbital), reduced price, and increased frequency to access space and the microgravity environment. With the increased dependence on data (demand, bandwidth, efficiency), space and the microgravity environment provide opportunities for optimized performance of these exotic optical fibers and glasses underlying the development of enabling technologies to meet future data demand. Existing terrestrial markets (Internet, telecommunications, market transactions) and emerging space markets (onorbit satellite servicing, space manufacturing, space resources, space communications, etc.) seem to converge, and this innovative material processing opportunity of exotic optical fibers and glasses might just be that ‘‘killer app’’: technologically competitive, economically viable, and with the ability to close the business case.

Ioana Cozmuta↗
NASA NTRS1974

Interaction of gases with ablative composites. II - Water

An investigation was conducted to study the sorption of water on two ablative composites and their components as a function of pressure and temperature. A pressure range from 0.001 to 10 torr and a temperature range from 25 to 35 C were considered in the investigation. It was found that the sorption of water vapor by the ablative composites and their components varied directly with pressure. The components of the ablative composites included phenolic spheres, cork, a carbon-glass fiber mixture, glass spheres, silica fibers, and a silicone elastomer.

Honeycutt, R. H., III↗
NASA NTRS2005

New Fiber Reinforced Waterless Concrete for Extraterrestrial Structural Applications

Commercial use of sulfur concrete on Earth is well established, particularly in corrosive, e.g., acid and salt, environments. Having found troilite (FeS) on the Moon raises the question of using extracted sulfur as a lunar construction mate: iii an attractive alternative to conventional concrete as it does not require water For the purpose of this paper it is assumed that lunar ore is mined, refined, and the raw sulfur processed with appropriate lunar regolith to form, for example, brick and beam elements. Glass fibers produced from regolith were used as a reinforcement to improve the mechanical properties of the sulfur concrete. Glass fibers and glass rebar were produced by melting the lunar regolith simulant. Lunar regolith stimulant was melted in a 25 cc Pt-Rh crucible in a Sybron Thermoline 46100 high temperature MoSi2 furnace at melting temperatures of 1450 to 1600G. The glass melt wets the ceramic rod and long continuous glass fibers were easily hand drawn. The glass fibers were immediately coated with a protective polymer to maintain the mechanical strength. The viability of sulfur concrete as a construction material for extraterrestrial application is presented. The mechanical properties of the glass fiber reinforced sulfur concrete were investigated.

Toutanji, H.↗
NASA NTRS1986

Fiber reinforced glasses and glass-ceramics for high performance applications

The development of fiber reinforced glass and glass-ceramic matrix composites is described. The general concepts involved in composite fabrication and resultant composite properties are given for a broad range of fiber and matrix combinations. It is shown that composite materials can be tailored to achieve high levels of toughness, strength, and elastic stiffness, as well as wear resistance and dimensional stability.

Prewo, K. M.↗
NASA NTRS2013

Compact Termination for Structural Soft-goods

Glass fiber is unique in its ability to withstand atomic oxygen and ultraviolet radiation in-space environments. However, glass fiber is also difficult to terminate by traditional methods without decreasing its strength significantly. Glass fiber products are especially sensitive to bend radius, and do not work very well with traditional 'sewn loop on pin' type connections. As with most composites, getting applied loads from a metallic structure into the webbing without stress concentrations is the key to a successful design. A potted end termination has been shown in some preliminary work to out-perform traditional termination methods. It was proposed to conduct a series of tensile tests on structural webbing or cord to determine the optimum potting geometry, and to then be able to estimate a weight and volume savings over traditional sewn-overa- pin connections. During the course of the investigation into potted end terminations for glass fiber webbing, a new and innovative connection was developed that has lower weight, reduced fabrication time, and superior thermal tolerance over the metallic end terminations that were to be optimized in the original proposal. This end termination essentially transitions the flexible glass fiber webbing into a rigid fiberglass termination, which can be bolted/fastened with traditional methods

Wilkes, Robert, Jr.↗
NASA NTRS1990

The feasibility of solar reflector production from lunar materials for solar power in space

Science Applications International Corporation (SAIC) investigated the feasibility of producing solar reflectors from indigenous lunar materials for solar power production on the moon. First, lunar construction materials and production processes were reviewed, and candidate materials for reflector production were identified. At the same time, lunar environmental conditions were reviewed for their effect on production of concentrators. Next, conceptual designs and fabrication methods were proposed and studied for production of dish concentrators and heliostats. Finally, fabrication testing was performed on small-scale models using earth analogs of lunar materials. Findings from this initial investigation indicate that production of concentrators from lunar materials may be an attractive approach for solar energy production on the moon. Further design and testing are required to determine the best techniques and approaches to optimize this concept. Four materials were identified as having high potential for solar reflector manufacture. These baseline materials were foamed glass, concrete with glass-fiber reinforcement, a glass-fiber/glass-melt composite, and an iron-glass sintered material.

Source record↗
NASA NTRS1981

Studies on the behavior of ammonia and ammonium salts in the atmosphere (1) - Fractional collection of ammonia gas and particulate ammonium

Methods for the fractional collection of trace amounts of atmospheric ammonia gas and ammonium particles on a two staged glass fiber filter are summarized. A standard glass fiber filter washed with distilled water and dried at 120 to 130 C was used. A second filter was impregnated with a mixture of 3% boric acid and 25% glycerin solution. The blank of glass fiber filters impregnated with a mixture of the above solution was very low for ammonia, i.e. 0.06 micrograms in a filter of 47 mm in diameter. The mean concentrations of ammonia and ammonium in air at Kawasaki, a polluted area, were 7.6 and 2.3 micrograms cu m, and those at Sanriku, an unpolluted area 0.9 and 0.2 micrograms cu m, respectively. Ratios of concentration levels of ammonium to total ammonia in the atmosphere were 0.3 and 0.2 for the polluted and unpolluted areas, respectively. Ammonium salts in air at both areas were not correlated with relative humidity. Variations in time of ammonia concentrations and sources in surrounding areas are also considered.

Kiin, K.↗
NASA NTRS1974

Study to determine and analyze the strength of high modulus glass in epoxy-matrix composites

Glass composition research was conducted to produce a high modulus, high strength beryllium-free glass fiber. This program was built on the previous research for developing high modulus, high strength glass fibers which had a 5 weight percent beryllia content. The fibers resulting from the composition program were then used to produce fiber reinforced-epoxy resin composites which were compared with composites reinforced by commercial high modulus glass fibers, Thornel S graphite fiber, and hybrids where the external quarters were reinforced with Thornel S graphite fiber and the interior half with glass fiber as well as the reverse hybrid. The composites were given tensile strength, compressive strength, short-beam shear strength, creep and fatigue tests. Comments are included on the significance of the test data.

Bacon, J. F.↗
NASA NTRS1995

Thermal Protection Studies of Synthetic And Woven Materials

This paper presents results of experimental study to evaluate the thermal protection properties of synthetic felt and woven materials using an NBS smoke chamber. The chamber was modified to record the weight loss of the samples, which in turn, indicated the effectiveness of the insulation material. The following materials were tested: (a) aluminoborosilicate cloth (NEXTEL); (b) fiber glass cloth; (c) carbonized polyaacrylonitrile and rayon cloth; (d) aromatic nylon felt; (e) SiC (NICALON) CLOTH; and (f) phenolic novolac (KYNOL) cloth. Samples of these were put in front of fiber glass batting containing 18% phenolic resin (Owens Corning PF-204). They were exposed to a radiant heat of 5w cm-2 which resulted in an almost complete resin mass loss within four minutes. Results of this study are shown in various figures, where the mass loss from the fiber glass batting is plotted vs. time. In these figures, solid curves show the percent mass loss of the exposed fiber glass and dashed curves indicate the loss in another fiber glass sample of the same initial mass protected by the material under test.

Saad, Michel A.↗
NASA NTRS2005

Glass and Glass-Ceramic Materials from Simulated Composition of Lunar and Martian Soils: Selected Properties and Potential Applications

In-situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. Within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using lunar and martian soils, and exploring various applications of these materials for planetary surface operations. Our preliminary work to date have demonstrated that glasses can be successfully prepared from melts of the simulated composition of both lunar and martian soils, and the melts have a viscosity-temperature window appropriate for drawing continuous glass fibers. The glasses are shown to have the potential for immobilizing certain types of nuclear wastes without deteriorating their chemical durability and thermal stability. This has a direct impact on successfully and economically disposing nuclear waste generated from a nuclear power plant on a planetary surface. In addition, these materials display characteristics that can be manipulated using appropriate processing protocols to develop glassy or glass-ceramic magnets. Also discussed in this presentation are other potential applications along with a few selected thermal, chemical, and structural properties as evaluated up to this time for these materials.

Ray, C. S.↗
NASA NTRS2007

Sequestration of Single-Walled Carbon Nanotubes in a Polymer

Sequestration of single-walled carbon nanotubes (SWCNs) in a suitably chosen polymer is under investigation as a means of promoting the dissolution of the nanotubes into epoxies. The purpose of this investigation is to make it possible to utilize SWCNs as the reinforcing fibers in strong, lightweight epoxy-matrix/carbon-fiber composite materials. SWCNs are especially attractive for use as reinforcing fibers because of their stiffness and strength-to-weight ratio: Their Young s modulus has been calculated to be 1.2 TPa, their strength has been calculated to be as much as 100 times that of steel, and their mass density is only one-sixth that of steel. Bare SWCNs cannot be incorporated directly into composite materials of the types envisioned because they are not soluble in epoxies. Heretofore, SWCNS have been rendered soluble by chemically attaching various molecular chains to them, but such chemical attachments compromise their structural integrity. In the method now under investigation, carbon nanotubes are sequestered in molecules of poly(m-phenylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene) [PmPV]. The strength of the carbon nanotubes is preserved because they are not chemically bonded to the PmPV. This method exploits the tendency of PmPV molecules to wrap themselves around carbon nanotubes: the wrapping occurs partly because there exists a favorable interface between the conjugated face of a nanotube and the conjugated backbone of the polymer and partly because of the helical molecular structure of PmPV. The constituents attached to the polymer backbones (the side chains) render the PmPV-wrapped carbon nanotubes PmPV soluble in organic materials that, in turn, could be used to suspend the carbon nanotubes in epoxy precursors. At present, this method is being optimized: The side chains on the currently available form of PmPV are very nonpolar and unable to react with the epoxy resins and/or hardeners; as a consequence, SWCN/PmPV composites have been observed to precipitate out of epoxies while the epoxies were being cured. If the side chains of the PmPV molecules were functionalized to make them capable of reacting with the epoxy matrices, it might be possible to make progress toward practical applications. By bonding the side chains of the PmPV molecules to an epoxy matrix, one would form an PmPV conduit between the epoxy matrix and the carbon nanotubes sequestered in the PmPV. This conduit would transfer stresses from the epoxy matrix to the nanotubes. This proposed load-transfer mode is similar to that of the current practice in which silane groups are chemically bonded to both the epoxy matrices and the fibers (often glass fibers) in epoxymatrix/fiber composites.

Bley, Richard A.↗