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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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Thin glass beam splitter, densitometer head, and densitometer electronics are incorporated in a standard contour projector. The density contour of small areas of photographic film can be read. This instrument can be used as a research tool in process engineering.
Simplified and improved electrometer circuit provides high-input impedance, stability of gain and operating point, linear response, and low power requirements.
Transistorized amplifier, in which an external reference voltage controls gain, combines high gain with stability and low power consumption. This circuit is useful in electronic servo and portable audio equipment.
Cathode support structure designed around a titanium diaphragm prevents radial misalignment between the cathode and anode in amplitrons. The titanium exhibits low thermal conductivity, tolerates lateral thermal expansion of the cathode, and is a poor primary and secondary emission medium.
Large compound curved surfaces for collecting and concentrating radiation are fabricated by the use of several common machining and forming processes. Lightweight sectors are assembled into large reflectors. With this concept of fabrication, integrally stiffened reflective sectors up to 25 square feet in area have been produced.
A mix of borax powder and a chlorinated anhydrous polyester resin yields a plastic composition that is fire-retardant, yields a minimum of toxic gases when heated, and exhibits high thermal insulating properties. This composition can be used as a coating or can be converted into laminated or cast shapes.
Web belt system measures belt or strap load. It is partially disassembled and installed on an existing belt without cutting or re-threading the belt. A strain gage, installed on one of the support beams, eliminates errors due to uneven loading.
Cold working and aging prepares nickel alloys for coiling into springs with properties acceptable in a cryogenic environment.
Nickel base alloy with high strength, ductility, good impact and oxidation resistance, microstructural stability, workability potential, and the ability to show improved strength and ductility when directly solidified has recently been developed for high temperature applications.
Polyimide P10P and its processing technique apply to most high temperature plastic products, devices and castings. Prepolymer, when used as varnish, impregnates fibers directly and is able to be processed into advanced composities. Material may also be used as molding powder and adhesive.
The state of the art was assessed with regards to efforts in support of the crop production estimation problem and alternative generic proportion estimation techniques were investigated. Topics covered include modeling the greeness profile (Badhwarmos model), parameter estimation using mixture models such as CLASSY, and minimum distance estimation as an alternative to maximum likelihood estimation. Approaches to the problem of obtaining proportion estimates when the underlying distributions are asymmetric are examined including the properties of Weibull distribution.
Efforts in support of the development of multicrop production monitoring capability are reported. In particular, segment level proportion estimation techniques based upon a mixture model were investigated. Efforts have dealt primarily with evaluation of current techniques and development of alternative ones. A comparison of techniques is provided on both simulated and LANDSAT data along with an analysis of the quality of profile variables obtained from LANDSAT data.
Contributions by minorities to the NASA programs are highlighted by profiles of 80 personnel. Educational and professional histories are summarized.
A series of low molecular weight perfluoroalkylethers (PFAE) were synthesized by direct fluorination. Viscosity-temperature properties and oxidation stabilities were determined. Viscosity-temperature correlations indicated that increases in branching and increases in the size of the branching substituent caused a deterioration in viscometric properties (i.e., an increase in ASTM slope). In addition, increasing the ratio of carbon to oxygen in these compounds also increased the ASTM slope. Preliminary oxidation stability tests indicated that highly branched PFAE fluids. (i.e., those containing quaternary carbons) may be less stable than either those containing a single trifluoromethyl pendant group or those containing no branching at all.
A series of low molecular weight perfluoroalkyl ethers (PFAEs) were synthesized by direct fluorination. Viscosity-temperature properties and oxidation stabilities were determined. Viscosity-temperature correlations indicated that increases in branching and increases in the size of the branching substituent caused a deterioration in viscometric properties (i.e., an increase in ASTM slope). In addition, increasing the ratio of carbon to oxygen in these compounds also increased the ASTM slope. Preliminary oxidation stability measurements indicated that highly branched PFAE fluids (i.e., those containing quaternary carbons) may be less stable than either those containing a single trifluoromethyl pendant group or those containing no branching at all.
A strategic plan for the U.S. space science and applications program during the next 5 to 10 years was developed and published in 1988. Based on the strategies developed by the advisory committees of both the National Academy of Science and NASA, the plan balances major, moderate, and small mission initiatives, the utilization of the Space Station Freedom, and the requirements for a vital research base. The Office of Space Science and Applications (OSSA) strategic plan is constructed around five actions: establish a set of programmatic themes; establish a set of decision rules; establish a set of priorities for missions and programs within each theme; demonstrate that the strategy will yield a viable program; and check the strategy for consistency within resource constraints. The OSSA plan is revised annually. This OSSA 1990 Strategic Plan refines the 1989 Plan and represents OSSA's initial plan for fulfilling its responsibilities in two major national initiatives. The Plan is now built on interrelated, complementary strategies for the core space science and applications program, for the U.S. Global Change Research Program, and for the Space Exploration Initiative. The challenge is to make sure that the current level of activity is sustained through the end of this century and into the next. The 1990 Plan presents OSSA's strategy to do this.
An outline of the Project Operations Branch at Goddard Space Flight Center is presented that describes the management of the division and each subgroup's responsibility. The paper further describes the development of software tools for the Macintosh personal computer, and their impending implementation. A detailed step by step procedure is given for using these software tools.
This booklet highlights the history of American aeronautical and aerospace research over a 75-year period. It begins with the activities of the National Advisory Committee for Aeronautics, which was established in 1915, and continues with the National Aeronautics and Space Administration. The chief accomplishments for each decade are listed. It concludes with President Bush's challenge to NASA to land people on Mars.