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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 163 records · Page 9

Ion beam sputtering of fluoropolymers

Etching and deposition of fluoropolymers are of considerable industrial interest for applications dealing with adhesion, chemical inertness, hydrophobicity, and dielectric properties. This paper describes ion beam sputter processing rates as well as pertinent characteristics of etched targets and films. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Also presented are sputter target and film characteristics which were documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs.

Sovey, J. S.↗

Hard Suit With Adjustable Torso Length

Torso sizing rings allow single suit to fit variety of people. Sizing rings inserted between coupling rings of torso portion of hard suit. Number of rings chosen to fit torso length of suit to that of wearer. Rings mate with, and seal to, coupling rings and to each other. New adjustable-size concept with cost-saving feature applied to other suits not entirely constructed of "hard" materials, such as chemical defense suits and suits for industrial-hazard cleanup.

Vykukal, Hubert C.↗

Monolithic GaAs digitizer for space-based laser pulse spreading effect

A 6-bit 1-GHz digitizer was designed to analyze the 1-ns pulse spreading effects in a space based altimeter. The digitizer consisted of four 4-bit flash A/D converters and a 6-bit encoder. Also, the converter utilized four 4-bit converters and a 4-to-6 bit encoder to achieve 6 bit resolution at the 1 GHz sample rate. The design was unique because it utilized only the inverters and NOR gates for the converters and encoder, hence it could be fabricated using the existing state-of-the-art GaAs processing techniques. This GHz digitizer has many commercial applications. It could be applicable to: (1) digital microwave transmission system for the telecommunication industries, (2) pulse monitoring in high kinetic chemical reactions, (3) transient signals in the medical field, and (4) microwave signals in astronomy.

Lao, Bennig↗

The resources of Mars for human settlement

Spacecraft exploration of Marshas shown that the essential resources necessary for life support are present on the Martian surface. The key life-support compounds O2, N2, and H2O are available on Mars. The soil could be used as radiation shielding and could provide many useful industrial and construction materials. Compounds with high chemical energy, such as rocket fuels, can be manufactured in-situ on Mars. Solar power, and possibly wind power, are available and practical on Mars. Preliminary engineering studies indicate that fairly autonomous processes can be designed to extract and stockpile Martian consumables.

Meyer, Thomas R.↗

Global atmospheric chemistry of CFC-123

The compound 1,1-dichloro--2,2,2-trifluoroethane (CFC-123) has been proposed as an industrial substitute for trichlorofluoromethane (CFC-11). The chemical destruction rates of CFC-123 by various processes is calculated here using a three-dimensional global model of the atmosphere, and it is confirmed that the chief sink of CFC-123 is destruction by OH radicals below 12 km, accounting for 88 percent of its loss. The calculated destruction rate is greatest in the equatorial region below 2 km. The calculated steady-state lifetime of CFC-123 is 1.5 years, much shorter than that of CFC-11, the destruction of which is largely confined to the stratosphere. For equal rates of CFC-123 and CFC-11 emission to the atmosphere, the molar content in the atmosphere and the injection rate of chlorine into the stratosphere are, respectively, 48 and 14 times greater for CFC-11 than for CFC-123 in steady state.

Prinn, Ronald G.↗

Aging Effects of Environmentally-Friendly Cleaners on Adhesive Bond Integrity

Because of the 1990 Clean Air Act Amendment many chlorinated solvents are being phased out of use in manufacturing industries. Replacement of the ODC (ozone- depleting chemicals) with less volatile, non-ozone depleting cleaners has been extensively studied over the past nine years at Thiokol Propulsion, Cordant Technologies. Many of the non-ODC cleaners contain compounds that can potentially degrade over time under conditions of high temperature, humidity and exposure to light. The chemical composition of environmentally conditioned cleaners and the subsequent effect on aluminum/amine-cured epoxy bond integrity as measured by Tapered Double Cantilever Beam were evaluated. From this study it is observed that moisture content increases for those cleaners containing polar compounds. Non-volatile residue content increases as stabilizers are depleted and the chemical compound limonene is oxidized. A change in aluminum/ amine-cured epoxy bond fracture toughness is observed as some of these cleaners age with increases in moisture and NVR content.

Biegert, L. L.↗

Solar Sail Propulsion for Planetary Missions

Solar sails have the potential to provide high ΔV for many types of missions. Solar sails are large, mirror-like structures made of a lightweight material that reflects sunlight to propel the spacecraft. The continuous solar photon pressure provides thrust with no need for the heavy, expendable propellants used by conventional chemical and electric propulsion systems. NASA, with industry partners, are developing and flying solar sails applicable to a wide range of space science missions, including those of interest for planetary science. Currently funded technology development activities support two classes of missions: Deep space interplanetary CubeSats (12 – 24 kg) and smallsats (up to ~125 kg).

Solar Sail↗

Spinoff from Space Fuel

In 1963, under contract with NASA, Air Products and Chemicals, Inc. built a 32 1/2 ton-a-day plant to meet the soaring demand for liquid hydrogen created by the Apollo missions and J-2 ground testing. Air Product's experience in government research, development and production of liquid hydrogen served as the springboard for a broad variety of practical, Earth-use applications. Today, liquid hydrogen is widely used among many industries including petroleum refineries in gasoline production and chemical and pharmaceutical firms in the manufacturing of fertilizers and drugs. New commercial applications are growing at the rate of about ten percent per year. Input from government research, Air Product's own technology development, and the large space program requirements combined to make the company the prime manufacturer of liquid hydrogen and enabled them to add a new 30-ton plant near New Orleans.

Source record↗

Catalysis and biocatalysis program

This final report presents a summary of research activities and accomplishments for the Catalysis and Biocatalysis Program, which was renamed the Biological and Chemical Technologies Research (BCTR) Program, currently of the Advanced Industrial Concepts Division (AICD), Office of Industrial Technologies of the Department of Energy (DOE). The Program was formerly under the Division of Energy Conversion and Utilization Technologies (ECUT) until the DOE reorganization in April, 1990. The goals of the BCTR Program are consistent with the initial ECUT goals, but represent an increased effort toward advances in chemical and biological technology transfer. In addition, the transition reflects a need for the BCTR Program to assume a greater R&D role in chemical catalysis as well as a need to position itself for a more encompassing involvement in a broader range of biological and chemical technology research. The mission of the AICD is to create a balanced Program of high risk, long-term, directed interdisciplinary research and development that will improve energy efficiency and enhance fuel flexibility in the industrial sector. Under AICD, the DOE Catalysis and Biocatalysis Program sponsors research and development in furthering industrial biotechnology applications and promotes the integrated participation of universities, industrial companies, and government research laboratories.

Ingham, J. D.↗

Survey of hydrogen production and utilization methods. Volume 1: Executive summary

The use of hydrogen as a synthetic fuel is considered. Processes for the production of hydrogen are described along with the present and future industrial uses of hydrogen as a fuel and as a chemical feedstock. Novel and unconventional hydrogen-production techniques are evaluated, with emphasis placed on thermochemical and electrolytic processes. Potential uses for hydrogen as a fuel in industrial and residential applications are identified and reviewed in the context of anticipated U.S. energy supplies and demands. A detailed plan for the period from 1975 to 1980 prepared for research on and development of hydrogen as an energy carrier is included.

Gregory, D. P.↗

Environment Monitor

Viking landers touched down on Mars equipped with a variety of systems to conduct automated research, each carrying a compact but highly sophisticated instrument for analyzing Martian soil and atmosphere. Instrument called a Gas Chromatography/Mass Spectrometer (GC/MS) had to be small, lightweight, shock resistant, highly automated and extremely sensitive, yet require minimal electrical power. Viking Instruments Corporation commercialized this technology and targeted their primary market as environmental monitoring, especially toxic and hazardous waste site monitoring. Waste sites often contain chemicals in complex mixtures, and the conventional method of site characterization, taking samples on-site and sending them to a laboratory for analysis is time consuming and expensive. Other terrestrial applications are explosive detection in airports, drug detection, industrial air monitoring, medical metabolic monitoring and for military, chemical warfare agents.

Source record↗

Processing of Water on the Moon

The electrolytic dissociation of water into gaseous forms of hydrogen and oxygen is a well known process that can quickly be summarized in a series of illustrations. Table 1 presents some physical properties of hydrogen and oxygen for purposes of reference. Figure 1 illustrates the chemical process and the equipment used in the industrial production of hydrogen and oxygen by the electrolysis of water. Table 2 summarizes the characteristics of electrolytic H2-O2 cells used in industrial practice. It is of interest to note that substantial amounts of power are required for the process and that rather heavy equipments are common to the land-based systems now in use. Very little can be done to reduce the power requirements, for the process as now carried out is relatively efficient, but undoubtedly great savings in weight can be realized.

Fowle, A. A.↗

Vacuum pumps and systems: A review of current practice

A review of the fundamental characteristics of the many types of vacuum pumps and vacuum pumping systems is given. The optimum pumping range, relative cost, performance limitations, maintenance problems, system operating costs and similar subjects are discussed. Experiences from the thin film deposition, chemical processing, material handling, food processing and other industries, as well as space simulation are used to support conclusions and recommendations.

Giles, Stuart↗

Space Shuttle solid rocket motor exposure monitoring

During the processing of the Space Shuttle Solid Rocket Booster (SRB), segments at the Kennedy Space Center, an odor was detected around the solid propellant. An Industrial Hygiene survey was conducted to determine the chemical identity of the SRB offgassing constituents. Air samples were collected inside a forward SRB segment and analyzed to determine chemical composition. Specific chemical analysis for suspected offgassing constituents of the propellant indicated ammonia to be present. A gas chromatograph mass spectroscopy (GC/MS) analysis of the air samples detected numerous high molecular weight hydrocarbons.

Brown, S. W.↗

Analysis, design and testing of high pressure waterjet nozzles

The Hydroblast Research Cell at MSFC is both a research and a processing facility. The cell is used to investigate fundamental phenomena associated with waterjets as well as to clean hardware for various NASA and contractor projects. In the area of research, investigations are made regarding the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current industrial methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents, and high pressure waterjet cleaning has proven to be a viable alternative. Standard methods of waterjet cleaning use hand held or robotically controlled nozzles. The nozzles used can be single-stream or multijet nozzles, and the multijet nozzles may be mounted in a rotating head or arranged in a fan-type shape. We consider in this paper the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage (e.g. the formation of 'islands' of material not cleaned) and damage to the substrate from the waterjet have been observed. In addition, current stripping operations require the nozzle to be placed at a standoff distance of approximately 2 inches in order to achieve adequate performance. This close proximity of the nozzle to the target to be cleaned poses risks to the nozzle and the target in the event of robot error or the striking of unanticipated extrusions on the target surface as the nozzle sweeps past. Two key motivations of this research are to eliminate the formation of 'coating islands' and to increase the allowable standoff distance of the nozzle.

Mazzoleni, Andre P.↗

Langmuir Probe Measurements in an Inductively Coupled Ar/CF4 Plasmas

Technological advancement in the microelectronics industry requires an understanding of the physical and chemical processes occurring in plasmas of fluorocarbon gases, such as carbon tetrafluoride (CF4) which is commonly used as an etchant, and their mixtures to optimize various operating parameters. In this paper we report data on electron number density (ne), electron temperature'(Te), electron energy distribution function (EEDF), mean electron energy, ion number density (ni), and plasma potential (Vp) measured by using Langmuir probe in an inductively coupled 13.56 MHz radio frequency plasmas generated in 50%Ar:50%CF4 mixture in the GEC cell. The probe data were recorded at various radial positions providing radial profiles of these plasma parameters at 10-50 mTorr pressures and 200 W and 300 W of RF power. Present measurements indicate that the electron and ion number densities increase with increase in pressure and power. Whereas the plasma potential and electron temperature decrease with increase in pressure, and they weakly depend on RF power. The radial profiles exhibit that the electron and ion number densities and the plasma potential peak at the center of the plasma with an exponential fall away from it, while the electron temperature has a minimum at the center and it increases steadily towards the electrode edge. The EEDFs have a characteristic drop near the low energy end at all pressures and pressures and their shapes represent non-Maxwellian plasma and exhibit more like Druyvesteyn energy distribution.v

Rao, M. V. V. S.↗

Computational Modeling in Structural Materials Processing

High temperature materials such as silicon carbide, a variety of nitrides, and ceramic matrix composites find use in aerospace, automotive, machine tool industries and in high speed civil transport applications. Chemical vapor deposition (CVD) is widely used in processing such structural materials. Variations of CVD include deposition on substrates, coating of fibers, inside cavities and on complex objects, and infiltration within preforms called chemical vapor infiltration (CVI). Our current knowledge of the process mechanisms, ability to optimize processes, and scale-up for large scale manufacturing is limited. In this regard, computational modeling of the processes is valuable since a validated model can be used as a design tool. The effort is similar to traditional chemically reacting flow modeling with emphasis on multicomponent diffusion, thermal diffusion, large sets of homogeneous reactions, and surface chemistry. In the case of CVI, models for pore infiltration are needed. In the present talk, examples of SiC nitride, and Boron deposition from the author's past work will be used to illustrate the utility of computational process modeling.

Meyyappan, Meyya↗

Gas-Liquid Two-Phase Flows Through Packed Bed Reactors in Microgravity

The simultaneous flow of gas and liquid through a fixed bed of particles occurs in many unit operations of interest to the designers of space-based as well as terrestrial equipment. Examples include separation columns, gas-liquid reactors, humidification, drying, extraction, and leaching. These operations are critical to a wide variety of industries such as petroleum, pharmaceutical, mining, biological, and chemical. NASA recognizes that similar operations will need to be performed in space and on planetary bodies such as Mars if we are to achieve our goals of human exploration and the development of space. The goal of this research is to understand how to apply our current understanding of two-phase fluid flow through fixed-bed reactors to zero- or partial-gravity environments. Previous experiments by NASA have shown that reactors designed to work on Earth do not necessarily function in a similar manner in space. Two experiments, the Water Processor Assembly and the Volatile Removal Assembly have encountered difficulties in predicting and controlling the distribution of the phases (a crucial element in the operation of this type of reactor) as well as the overall pressure drop.

Motil, Brian J.↗