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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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Low-cost metal tube reducer accepts tubing up to 1 inch outer diameter and can reduce this diameter to less than 1/2 inch with controlled wall thickness. This device can reduce all of the tube without waste. It produces extremely good surface finishes.
Effects of strain rate, temperature, crystallinity, and surface finish /smoothness/ on the tensile strength of a commercial chlorotrifluorethylene plastic /CTFE/ used for lipseals in very fast-acting liquid oxygen valves.
Tests to determine the tensile and fatigue properties of Inconel 718 at cryogenic temperatures show that the alloy increases in strength at low temperatures, with very little change in toughness. The effect of surface finish and grain size on the fatigue properties was also determined.
Research program studies behavior of specific high-speed, angular-contact ball bearings. Program is aimed at detailed investigation of ball-separator behavior and lubrication surface-finish effects in a specific gyro wheel.
Thermionic converter improvements by electronegative additives and emitter surface finishes, noting cesium oxide, heat treatments with electropolishing, electroetching, etc
Corrosion and stress effects separation in stress corrosion of Al-Zn-Mg-Cu alloy, considering machined surface finishing role
Fluorel spectral reflectance, transmittance and absorptance under monochromatic irradiation, considering thermal analysis and surface finish
Surveyor 3 thermal control surfaces analysis from Apollo 12 samples collection, discussing spectral reflectance and lunar dust effects on surface finishes optical properties
Electro-chemical grinding technique has rotation speed control, constant feed rates, and contour control. Hypersonic engine parts of nickel alloys can be almost 100% machined, keeping tool pressure at virtual zero. Technique eliminates galling and permits constant surface finish and burr-free interrupted cutting.
A review of a comprehensive experimental investigation of the heat transfer and boundary layer in 30 deg to 15 deg and 60 deg to 15 deg conical nozzles is presented. The experiments were conducted with air at a stagnation temperature of 539 K (970 R) and throat Reynolds numbers based on a diameter ranging from 6 x 10 to the 5th power to 5 x 10 to the 6th power. Nozzle wall surface finish was varied from a smooth machine finish to a 826 x 10 to the minus 6th power cm (325 x 10 to the minus 6th in.) rms sandblasted finish. Measured heat transfer and wall temperatures are tabulated.
A part of the lower side of the main wing at the joint of the main spar with the fuselage frame was investigated. This wing beam area was simulated by a test specimen consisting of a spar boom of AZ 74 forging (7075 aluminum alloy modified with 0.3 percent Ag) and a portion of a honeycomb sandwich panel attached to the boom flange with steel bolts. The cross section was reduced to half scale. However, the flange thickness, the panel height, and the bolt size were full scale. Further, left and right portions of the fuselage frame intended to carry over the bending moment of the main wing were tested. Each of these frame halves consisted of a forward and a rear forging (7079 aluminum alloy, overaged) connected by an outer and inner skin (Alclad 7075) creating a box beam. These test specimens were full scale and were constructed principally of ordinary aircraft components. The test load spectrum was common to both types of specimens with regard to percentage levels. It consisted of maneuver and gust loads, touchdown loads, and loads due to ground roughness. A load history of 200 hours of flight with 15,000 load cycles was punched on a tape. The loads were randomized in groups according to the flight-by-flight principle. The highest positive load level was 90 percent of limit load and the largest negative load was -27 percent. A total of 20 load levels were used. Both types of specimens were provided with strain gages and had a nominal stress of about 300 MN/sq m in some local areas. As a result of the tests, steps were taken to reduce the risk of fatigue damage in aircraft. Thus stress levels were lowered, radii were increased, and demands on surface finish were sharpened.
A thermal control system was incorporated into the Lunar Roving Vehicle (LRV) to maintain temperature sensitive components within appropriate temperature limits during the translunar transportation phase, lunar surface operation, and quiescent periods between lunar traverses. This paper describes the thermal control system and discusses its thermal characteristics during all phases of operation. The basic concept is a passive system which stores internally generated energy during operation with subsequent radiation to space. The external environments are regulated by selected radiative surface finishes. Multi-layer insulation blankets, space radiators, flexible thermal straps, and fusible mass heat sinks were designed to control the temperatures of the electronic components.
Chemical processes presented in this document include cleaning, pickling, surface finishes, chemical milling, plating, dry film lubricants, and polishing. All types of chemical processes applicable to aluminum, for example, are to be found in the aluminum alloy section. There is a separate section for each category of metallic alloy plus a section for non-metals, such as plastics. The refractories, super-alloys and titanium, are prime candidates for the space shuttle, therefore, the chemical processes applicable to these alloys are contained in individual sections of this manual.
It is shown that in the early stages of design, scoring and fatigue failure of gear contact surfaces can be prevented by the following means: improving load capacity with the aid of tip relief, or by improved surface finish; by giving special care to the location and application of the lubricant in high-speed or high-load gear applications; by determining the thickness of the elastohydrodynamic film from an analysis for the worst temperature, speed, and load conditions, and selecting the appropriate lubricant from this analysis; by using an additive in the case of frequent repeated startup and shutdown conditions; by taking the expected temperature, speed, and load in the selection of an extreme pressure additive; and by systematically testing any new transmission or gear box design.
Eight slip ring capsules, each having 80 or 100 circuits, were operated for time periods ranging from 14,300 hours to 24,700 hours. The test mode simulated the motion of gimbal axes of the Saturn inertial guidance the platform in an organic free nitrogen environment. Computer-compiled noise data (approximately 45,000 recordings) were graphed as a function of test time and position within the capsules and as extreme probability distributions. Greater than ninety-nine percent of the noise measurements for the capsules with sufficient lubrication were less than 10 milliohms. Capsules with glass dielectrics did not perform significantly differently than those with filled epoxy dielectrics. The initial wear mode of prow formation was followed by rider wear. After 10 to the 8th power wipes, ring wear depth did not exceed the surface finish and the radial rider wear depth was less than 13 microns.
Set of standards in the form of drawings provides detailed information about materials fastening techniques, surface finishes, critical dimensions, quality control specifications, and installation methods for variety of static and total pressure tube instrumentation.
Various factors in Schottky barrier solar cell fabrication are evaluated in order to improve understanding of the current flow mechanism and to isolate processing variables that improve efficiency. Results of finger design, substrate resistivity, surface finishing and activation energy studies are detailed. An increased fill factor was obtained by baking of the vacuum system to remove moisture.
The paper describes the selection, development and qualification of the surface tension system and includes results of low-g drop tower tests of scale models, 1-g simulation tests of low-g large ullage settling and liquid withdrawal, structural qualification tests, and propellant surface tension/contact angle studies. Subscale testing and analyses were used to evaluate the ability of the system to maintain or recover the desired propellant orientation following possible disturbances during the Viking mission. This effort included drop tower tests to demonstrate that valid wick paths exist for moving any displaced propellant back over the tank outlet. Variations in surface tension resulting from aging, temperature, and lubricant contamination were studied and the effects of surface finish, referee fluid exposure, aging, and lubricant contamination on contact angle were assessed. Results of movies of typical subscale drop tower tests and full scale slosh tests are discussed.