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  • Other Sources  (657)
  • AERODYNAMICS  (479)
  • NONMETALLIC MATERIALS  (178)
  • Biochemistry and Biotechnology
  • Inorganic Chemistry
  • 1980-1984  (657)
  • 1925-1929
  • 1983  (657)
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Source
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  • 1980-1984  (657)
  • 1925-1929
Year
  • 1
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    Viscous wing code development: A 3-D viscid-inviscid interactive analysis (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 607-63
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  • 2
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    Computation of separated flow on airfoils with the Grumfoil code (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 557-58
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  • 3
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    Analysis of airfoil transitional separation bubbles (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 539-55
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  • 4
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    Entropy effects and shock fitting in conical supersonic full potential flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 461-49
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  • 5
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    Surface crystallization of a fluoride glass (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Growth of crystals on the surface of a Zr-Ba-La fluoride glass was observed by optical and scanning electron microscopy. Small, dark crystal nucleated rapidly and grew to a size of about 10 microns; then they stopped growing, and wrinkled regions emerged, covering the entire crystal surface.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society, Communications (ISSN 0002-7820); 66; C-132
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  • 6
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    Thermal oxidative degradation reactions of linear perfluoroalkyl ethers (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Thermal and thermal oxidative stability studies were performed on linear perfluoroalkyl ether fluids. The effect on degradation by metal catalysts and degradation inhibitors is reported. The linear perfluoroalkyl ethers are inherently unstable at 316 C in an oxidizing atmosphere. The metal catalysts greatly increased the rate of degradation in oxidizing atmospheres. In the presence of these metals in an oxidizing atmosphere, the degradation inhibitors were highly effective in arresting degradation at 288 C. However, the inhibitors had only limited effectiveness at 316 C. The metals promote degradation by chain scission. Based on elemental analysis and oxygen consumption data, the linear perfluoroalkyl ether fluids have a structural arrangement based on difluoroformyl and tetrafluoroethylene oxide units, with the former predominating. Previously announced in STAR as N82-26468
    Keywords: NONMETALLIC MATERIALS
    Type: I&EC - Industrial and Engineering Chemistry, Product Research and Development (ISSN 0196-4321); 22; 166-170
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  • 7
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    Fracture mechanics of cellular glass (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The fracture mechanics of cellular glasses (for the structural substrate of mirrored glass for solar concentrator reflecting panels) are discussed. Commercial and developmental cellular glasses were tested and analyzed using standard testing techniques and models developed from linear fracture mechanics. Two models describing the fracture behavior of these materials were developed. Slow crack growth behavior in cellular glass was found to be more complex than that encountered in dense glasses or ceramics. The crack velocity was found to be strongly dependent upon water vapor transport to the tip of the moving crack. The existence of a static fatigue limit was not conclusively established, however, it is speculated that slow crack growth behavior in Region 1 may be slower, by orders of magnitude, than that found in dense glasses. Previously announced in STAR as N82-11209
    Keywords: NONMETALLIC MATERIALS
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  • 8
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    Simulated space radiation effects on dielectrics and coatings (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Simulation tests of space radiation have been performed for specific organic and inorganic materials. The test results for fifteen materials exposed to protons and five exposed to electrons are presented.
    Keywords: NONMETALLIC MATERIALS
    Type: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-30; 4090-409
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  • 9
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    The effect of annealing on the creep of plasma-sprayed ceramics (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The creep of plasma sprayed ZrO2-8Y2O3 was measured at temperatures from 98 to 1250 C (180 to 220 F), and compared to creep of identical samples after annealing at temperatures from 98 to 1316 C (1800 to 2400 F). Loads and temperatures which produced significant creep of as sprayed ceramics produced no creep after annealing. Previously announced in STAR as N83-24799
    Keywords: NONMETALLIC MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 4; 819-827
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  • 10
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    Residual stress in plasma-sprayed ceramic turbine tip and gas-path seal specimens (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The residual stresses in a ceramic sheet material used for turbine blade tip gas path seals, were estimated. These stresses result from the plasma spraying process which leaves the surface of the sheet in tension. To determine the properties of plasma sprayed ZrO2-Y2O3 sheet material, its load deflection characteristics were measured. Estimates of the mechanical properties for sheet materials were found to differ from those reported for plasma sprayed bulk materials. Previously announced in STAR as N83-28380
    Keywords: NONMETALLIC MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 4; 802-809
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  • 11
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    Correlation of compressive and shear stress with spalling of plasma-sprayed ceramic materials (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Ceramics on metal substrates for potential use as high temperature seals or other applications are exposed to forces originating from differences in thermal expansion between the ceramic and the metal substrate. This report develops a relationship between the difference in expansion of the ceramic and the substrate, defines conditions under which shear between the ceramic and the substrate occurs, and those under which bending forces are produced in the ceramic. The off-axis effect of compression forces resulting from high temperature plastic flow of the ceramic producing buckling of the ceramic is developed. Shear is associated with the edge or boundary stresses on the component while bending is associated with the distortion of an interior region. Both modes are significant in predicting life of the ceramic. Previously announced in STAR as N83-27016
    Keywords: NONMETALLIC MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 4; 810-818
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  • 12
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    An exploratory study of area-efficient vortex flap concepts (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The potential of planform modification and hinge-line relocation to improve the thrust efficiency of vortex flaps was experimentally investigated on a 60-deg cropped delta wing model. Spanwise segmentation of the flap, together with chord-tailoring of the segments, allowed the vortex to be maintained on the outboard flap surfaces to higher angles of attack. In addition, location of the flap hinge aft of and underneath the wing leading edge generated substantial thrust from the vortex suction acting on the leading-edge lower surface. A combination of these beneficial effects allowed the flap/wing area to be reduced from 11.4 percent of the continuous flap to 6.3 percent of segmented flap, essentially without detriment to the incremental lift-to-drag ratio due to flap addition in the lift coefficient range 0.5-0.7 based on the basic wing area.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 20; 1062-106
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  • 13
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    Observations and implications of natural laminar flow on practical airplane surfaces (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 20, p. 3138, Accession no. A82-40893
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 20; 993-1006
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  • 14
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    Ultrasonic mixing of epoxy curing agents (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new technique for mixing solid curing agents into liquid epoxy resins using ultrasonic energy was developed. This procedure allows standard curing agents such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents with very high melt temperatures such as 4,4 prime-diaminodiphenyl sulfone (4,4 prime-DDS) and its 3,3 prime-isomer, (3,3 prime-DDS) to be mixed without prior melting of the curing agent. It also allows curing agents with very high melt temperatures such as 4,4 prime-diaminobenzophenone (4,4 prime-DABP) (242 C) to be mixed without premature curing. Four aromatic diamines were ultrasonically blended into MY-720 epoxy resin. These were 4, 4 prime-DDS; 3,3 prime-DDA; 4, 4 prime-DABP and 3,3 prime-DABP. Unfilled moldings were cast and cured for each system and their physical and mechanical properties compared. Previously announced in STAR as N83-27018
    Keywords: NONMETALLIC MATERIALS
    Type: SAMPE Quarterly (ISSN 0036-0821); 14; 46-50
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  • 15
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    Hardness of dense beta-Si3N4 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The effects of small changes in the concentration of an oxygen content densification aid on the room temperature microhardness of hot isostatically pressed and sintered beta-Si3N4 ceramics are studied. The compositions studied were Si3N4 containing 7 wt. pct BeSiN2, a fixed nonoxide densification aid, and 1.9-3.7 wt. pct oxygen as a second, variable densification aid. A proportional relationship between high density and high oxygen content, regardless of heat treatment type, is noted.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Materials Science Letters (ISSN 0261-8028); 2; 657-659
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  • 16
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    Stability of shock waves attached to wedges and cones (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 799, Accession no. A82-17876
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1611-161
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  • 17
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    Stability of silica heat shield materials in the Space Shuttle environment (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Sample tiles of Space Shuttle reusable surface insulation (RSI) and fibrous refractory composite insulation (FRCI) have been alternately exposed to simulated mission heating and the Kennedy Space Center launch-pad environment for up to 50 cycles. The two types of tiles were coated with an identical glass composition. The coating on RSI tiles was prone to cracking in the test environment while the same coating on FRCI was not. Absorption of water contaminated with environmental deposits resulted in accelerated devitrification in the RSI tiles. Devitrification in FRCI tiles was significantly less. The rate of environmental degradation of tiles appeared to be dependent on the amount of water absorption.
    Keywords: NONMETALLIC MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 4; 564-577
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  • 18
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    Surface chemistry, friction, and wear of Ni-Zn and Mn-Zn ferrites in contact with metals (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: X-ray photoelectron and Auger electron spectroscopy analysis were used in sliding friction experiments. These experiments were conducted with hot-pressed polycrystalline Ni-Zn and Mn-Zn ferrites, and single-crystal Mn-Zn ferrite in contact with various transition metals at room temperature in both vacuum and argon. The results indicate that Ni2O3 and Fe3O4 were present on the Ni-Zn ferrite surface in addition to the nominal bulk constituents, while MnO2 and Fe3O4 were present on the Mn-Zn ferrite surface in addition to the nominal bulk constituents. The coefficients of friction for the ferrites in contact with metals were related to the relative chemical activity of these metals. The more active the metal, the higher is the coefficient of friction. The coefficients of friction for the ferrites were correlated with the free energy of formation of the lowest metal oxide. The interfacial bond can be regarded as a chemical bond between the metal atoms and the oxygen anions in the ferrite surfaces. The adsorption of oxygen on clean metal and ferrite does strengthen the metal-ferrite contact and increase the friction. The ferrites exhibit local cracking and fracture with sliding under adhesive conditions. All the metals transferred to the surfaces of the ferrites in sliding. Previously announced in STAR as N83-19901
    Keywords: NONMETALLIC MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 4; 674-693
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  • 19
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    Shrinkage of amorphous silica fibers (1983)
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    Publication Date: 2011-08-18
    Description: By the application of a new technique, the viscosity of amorphous silica fibers was determined in the 1100-1350 C temperature range. An equation was derived that describes the kinetics of shrinkage of the fibers in terms of their radius, viscosity, and surface tension.
    Keywords: NONMETALLIC MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 4; 492-501
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  • 20
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    Phase distributions in plasma-sprayed zirconia-yttria (1983)
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    Publication Date: 2011-08-18
    Description: The distribution of phases in plasma-sprayed zirconia-yttria has been determined over a range of yttria levels from 0 to 26.1 molpct YO(1.5) using room temperature X-ray diffractometry. Pure, plasma-sprayed zirconia is composed almost entirely of the monoclinic phase. At levels of yttria between 4 and 10 percent, a quenched-in tetragonal phase predominates, and at higher levels the cubic phase predominates. The phase distributions are compared with previously reported test lives of thermal barrier coatings formed from these materials. Regions of optimal lives were found to correlate with regions having high amounts of the tetragonal phase, small but nonzero amounts of the monoclinic phase, and little or none of the cubic phase. Possible relationships between phase composition and coating performance are discussed.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society Bulletin (ISSN 0002-7812); 62; 1355-135
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  • 21
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    Development of plane strain fracture toughness test for ceramics using Chevron notched specimens (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Chevron-notched four-point-bend and short-bar specimens have been used to determine the fracture toughness of sintered aluminum oxide and hot-pressed silicon nitride ceramics. The fracture toughness for Si3N4 is found to be essentially independent of the specimen size and chevron notch configuration, with values ranging from 4.6 to 4.9 MNm exp -3/2. In contrast, significant specimen size and notch geometry effects have been observed for Al2O3, with the fracture toughness ranging from 3.1 to 4.7 MNm exp -3/2. These effects are attributed to a rising crack growth resistance curve for the Al2O3 tested.
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  • 22
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    A chimera grid scheme (1983)
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    Publication Date: 2011-08-18
    Description: A mesh system composed of multiple overset body-conforming grids is described for adapting finite-difference procedures to complex aircraft configurations. In this so-called 'chimera mesh,' a major grid is generated about a main component of the configuration and overset minor grids are used to resolve all other features. Methods for connecting overset multiple grids and modifications of flow-simulation algorithms are discussed. Computational tests in two dimensions indicate that the use of multiple overset grids can simplify the task of grid generation without an adverse effect on flow-field algorithms and computer code complexity.
    Keywords: AERODYNAMICS
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  • 23
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    Microstructural characterization of SiC (SCS) filaments (1983)
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    Publication Date: 2011-08-18
    Description: Microstructural features of SiC('SCS') fibers demonstrating growth properties have been investigated using scanning and transmission electron microscopy. An etchant of fused KOH:KNO3 was developed which adequately brought out previously undetermined features.
    Keywords: NONMETALLIC MATERIALS
    Type: SAMPE Quarterly (ISSN 0036-0821); 14; 39-45
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  • 24
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    Conservative full-potential calculations for axisymmetric, transonic flow (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 17, p. 2873, Accession no. A81-38082
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1492-149
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  • 25
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    Study of molecular deformation mechanisms in the glassy state. I - Temperature effect on stress-birefringence and strain-birefringence responses of poly(methyl methacrylate) (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Polymer Science: Polymer Physics Edition (ISSN 0098-1273); 21; 1647-166
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  • 26
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    Electrically conductive black optical paint (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An electrically conductive flat black paint has been developed for use on the Galileo spacecraft which will orbit Jupiter in the late 1980s. The paint, designed for equipment operating in high-energy radiation fields, has multipurpose functions. Its electrical conductivity keeps differential charging of the spacecraft external surfaces and equipment to a minimum, preventing the buildup of electrostatic fields and arcing. Its flat black aspect minimizes the effects of stray light and unwanted reflectances, when used in optical instruments and on sunshades. Its blackness is suitable, also, for thermal control, when the paint is put on spacecraft surfaces. The paint has good adherence properties, as measured by tape tests, when applied properly to a surface. The electrically conductive paint which was developed has the following characteristics: an electrical resistivity of 5 x 10 to the 7th ohms per square; a visual light total reflectance of approximately 5 percent; an infrared reflectance of 0.13 measured over a spectrum from 10 to the (-5.5) power to 0.001 meter; a solar absorptivity, alpha-s, of 0.93, and a thermal emissivity, epsilon, of 0.87, resulting in an alpha-s/epsilon of 1.07. The formula for making the paint and the process for applying it are described.
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  • 27
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    Characteristics of Si3N4-SiO2-Ce2O3 compositions sintered in high-pressure nitrogen (1983)
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    Publication Date: 2011-08-18
    Description: Full-density Si3N4-SiO2-Ce2O3 compositions were prepared by sintering with 2.5 MPa nitrogen pressure at temperatures of 1900 and 2090 C. Room-temperature flexural strengths near 700 MPa for sintered material compared favorably with the strength of hot-pressed material. At 1370 C, where flexural strengths as high as 363 MPa were obtained, it was observed that the coarsest structure was the strongest and the finest structure was the weakest. One of the compositions tested, Si3N4-8.7 wt pct SiO2-8.3 wt pct-Ce2O3, was found to have excellent 200-h oxidation resistance at 700, 1000, and 1370 C, without incidence of 700 to 1000 C phase instability and cracking.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society, Journal (ISSN 0002-7820); 66; 835-841
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  • 28
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    Molecular deformation and stress-strain behavior of poly(bisphenol-A-diphenyl sulfone) (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The strain-birefringence response of poly(bisphenol-A-diphenyl sulfone) is found to be independent of temperature at temperatures below -100 C; at higher temperatures, the response becomes slightly dependent on temperature, with lower birefringence seen at higher temperatures. The stress-strain behavior and the stress-birefringence response both depend on temperature over the entire testing temperature range (-179 C to 150 C) studied; this dependence, however, is not pronounced. The evidence is seen as suggesting that the polymer molecules respond to deformation by undergoing conformational rearrangements; the mode of the molecular deformation remains unchanged for temperatures of -100 C or lower. At higher temperatures, the average length of the chain segments involved in the rearrangement increases. The stress-strain response is attributed mainly to chain orientation. The entropic contribution deriving from chain orientation at temperatures below -100 C is still substantial. The modest temperature dependence of the stress-strain response suggests that the energy barriers for the chain segments involved in the rearrangement are relatively low.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Applied Physics (ISSN 0021-8979); 54; Oct. 198
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  • 29
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    Photothermal degradation of ethylene/vinylacetate copolymer (1983)
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    Publication Date: 2011-08-18
    Description: Photothermal degradation studies were conducted on a 'stabilized' formulation of ethylene/vinyl acetate copolymer (EVA) in the temperature range 25-105 C under three different oxygen environments (in open air, with limited access to O2, and in a dark closed stagnant oven). These studies were performed in order to evaluate the utility of EVA as an encapsulation material for photovoltaic modules. Results showed that at low temperature (25 C), slow photooxidation of the polymer occurred via electronic energy transfer involving the UV absorber incorporated in the polymer. However, no changes in the physical properties of the bulk polymer were detected up to 1500 hours of irradiation. At elevated temperatures, leaching and evaporation of the additives occurred, which ultimately resulted in the chemical crosslinking of the copolymer and the formation of volatile photoproducts such as acetic acid.
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  • 30
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    The structure of boron in boron fibres (1983)
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    Publication Date: 2011-08-18
    Description: The structure of noncrystalline, chemically vapour-deposited boron fibres was investigated by computer modelling the experimentally obtained X-ray diffraction patterns. The diffraction patterns from the models were computed using the Debye scattering equation. The modelling was done utilizing the minimum nearest-neighbour distance, the density of the model, and the broadening and relative intensity of the various peaks as boundary conditions. The results suggest that the fibres consist of a continuous network of randomly oriented regions of local atomic order, about 2 nm in diameter, containing boron atoms arranged in icosahedra. Approximately half of these regions have a tetragonal structure and the remaining half a distorted rhombohedral structure. The model also indicates the presence of many partial icosahedra and loose atoms not associated with any icosahedra. The partial icosahedra and loose atoms indicated in the present model are in agreement with the relaxing sub-units which have been suggested to explain the anelastic behavior of fibre boron and the loosely bound boron atoms which have been postulated to explain the strengthening mechanism in boron fibres during thermal treatment.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Materials Science (ISSN 0022-2461); 18; Sept
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  • 31
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    Injection slot location for boundary-layer control in shock-induced separation (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 18, p. 726, Accession no. A78-41866
    Keywords: AERODYNAMICS
    Type: (ISSN 0021-8669)
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  • 32
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    Lower-curing-temperature PMR polyimides (1983)
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    Publication Date: 2011-08-18
    Description: Partial substitution of a p-aminostyrene end-cap for the monomethyl ester of 5-norbornene-2, 3-dicarboxylic acid lowered the final cure temperature of typical PMR resins from 600 F to 500 F. The weight loss characteristics of neat resins and graphite fiber composites prepared by using the mixed end-cap approach were determined at 600 F. The room temperature and short-time elevated temperature mechanical properties of the composites at 550 F and 600 F were determined. The mechanical property retention characteristics of the composites at 550 F and 600 F are discussed. Previously announced in STAR as N83-10118
    Keywords: NONMETALLIC MATERIALS
    Type: Polymer Composites (ISSN 0272-8397); 4; July 198
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  • 33
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    Dynamic fatigue of a machinable glass-ceramic (1983)
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    Details
    Publication Date: 2011-08-18
    Description: To assess the stress-corrosion susceptibility of a machinable glass-ceramic, its dynamic fatigue behavior was investigated by measuring its strength as a function of stress rate. Fracture mechanics techniques were used to analyze the results for the purpose of making lifetime predictions for components of this material. This material was concluded to have only moderate resistance (N = 30) to stress corrosion in ambient conditions. The effects of specimen size on strength were assessed for the material used in this study; it was concluded that the Weibull edge-flaw scaling law adequately describes the observed strength-size relation.
    Keywords: NONMETALLIC MATERIALS
    Type: (ISSN 0002-7820)
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  • 34
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    Experimental determination of vapor species from laser-ablated carbon phenolic composites (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previosuly cited in issue 17, p. 2910, Accession no. A81-39069
    Keywords: NONMETALLIC MATERIALS
    Type: (ISSN 0001-1452)
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  • 35
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    Surface analyses of carbon fibers produced from polyacrylonitrile fibers at low carbonization temperatures (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A process for producing carbon fibers from polyacrylonitrile at low carbonization temperatures was studied. The bulk and surface properties of fibers obtained after reaction with benzoic acid, air and carbonizing in nitrogen or a dilute acetylene atmosphere are discussed. All fiber products had different surface and internal compositions. Samples produced at temperatures up to 950 C and carbonized in nitrogen contained substantial quantities of nitrogen and oxygen at the surface. During carbonization, the surface nitrogen converted into two new forms, possibly nitrile and an azo or a new carbon-nitrogen bond. Samples carbonized in acetylene contained a carbon-rich surface stable to oxidation.
    Keywords: NONMETALLIC MATERIALS
    Type: Textile Research Journal (ISSN 0040-5175); 53; July 198
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  • 36
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    Cavitation erosion characteristics of poly(methyl methacrylate) in a rotating disk device (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The cavitation erosion behavior including the initiation, dynamics and mechanism of damage process on perspex and epoxy resin specimens tested in a rotating disk device were discussed with respect to exposure time. The inception of erosion always took place at the location nearest to the center of rotation of the disk. Subsequently, as exposure time increased, erosion initiated at other locations as well. Light optical photographs and scanning electron micrographs clearly indicate that most of the material loss appears to occur form the networks of cracks due to their interaction and pits indicate particle debris. The optical degradation (loss of transmittance) on perspex was observed to be more on the rear side than on the front side. Previously announced in STAR as N83-11329
    Keywords: NONMETALLIC MATERIALS
    Type: (ISSN 0043-1648)
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  • 37
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    Comprehensive missile aerodynamics programs for preliminary design (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 12, p. 1851, Accession no. A82-27106
    Keywords: AERODYNAMICS
    Type: (ISSN 0022-4560)
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  • 38
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    Equivalent angle-of-attack method for estimating nonlinear aerodynamics of missile fins (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 19, p. 2971, Accession no. A82-39113
    Keywords: AERODYNAMICS
    Type: (ISSN 0022-4560)
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  • 39
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    Aerodynamics of wraparound fins (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 07, p. 863, Accession no. A83-21011
    Keywords: AERODYNAMICS
    Type: (ISSN 0022-4560)
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  • 40
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    Numerical calculation of nonlinear aerodynamics of wing-body configurations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 07, p. 864, Accession no. A83-21022
    Keywords: AERODYNAMICS
    Type: (ISSN 0001-1452)
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  • 41
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    Benchmark determination of Shuttle Orbiter entry aerodynamic heat-transfer data (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 07, p. 965, Accession no. A82-19777
    Keywords: AERODYNAMICS
    Type: (ISSN 0022-4560)
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  • 42
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    Computation of high Reynolds number internal/external flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 17, p. 2878, Accession no. A81-39001)
    Keywords: AERODYNAMICS
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  • 43
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    Ultrahigh Molecular Weight Aromatic Siloxane Polymers (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-11
    Description: Silphenylene-siloxane polymers can be prepared by a condensation reaction of a diol 1,4-bis(hydroxydimethylsilyl)benzene and a silane bis(dimethylamino)dimethylsilane. Using a stepwise condensation technique, a polymer (R=CH3) with a molecular weight in excess of 1.0 x 1 million has been produced. The polymer exhibits increased thermal stability, compared to a methyl siloxane polymer without the aromatic phenyl ring in the backbone. The use of bis(dimethylamino)methylvinylsilane should allow for ready crosslinking at the vinyl sites (R=-CH=CH2) introduced into the backbone. However, under the conditions of the reaction system a high molecular weight polymer was not obtained or the polymer underwent a crosslinking process during the synthesis.
    Keywords: NONMETALLIC MATERIALS
    Type: Alabama Univ. Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 13 p
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  • 44
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    Comparison of subsonic/transonic aftbody flow prediction methods (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 21, p. 3614, Accession no. A81-44900)
    Keywords: AERODYNAMICS
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  • 45
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    Linear/nonlinear behavior in unsteady transonic aerodynamics (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 12, p. 1923, Accession no. A81-29496)
    Keywords: AERODYNAMICS
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  • 46
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    Effects of spanwise blowing and reverse thrust on fighter low-speed aerodynamics (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 07, p. 963, Accession no. A82-19203)
    Keywords: AERODYNAMICS
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  • 47
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    Computation of nonequilibrium, supersonic three-dimensional inviscid flow over blunt-nosed bodies (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2120, Accession no. A75-33931
    Keywords: AERODYNAMICS
    Type: (ISSN 0001-1452)
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  • 48
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    Separated trailing-edge flow at a transonic Mach number (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 800, Accession no. A82-17899
    Keywords: AERODYNAMICS
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  • 49
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    Unsteady transonic small disturbance approximation with strong shock waves (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 797, Accession no. A82-17812
    Keywords: AERODYNAMICS
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  • 50
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    Grid generation in three dimensions by Poisson equations with control of cell size and skewness at boundary surfaces (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An algorithm for generating computational grids about arbitrary three-dimensional bodies is developed. The elliptic partial differential equation (PDE) approach developed by Steger and Sorenson and used in the NASA computer program GRAPE is extended from two to three dimensions. Forcing functions which are found automatically by the algorithm give the user the ability to control mesh cell size and skewness at boundary surfaces. This algorithm, as is typical of PDE grid generators, gives smooth grid lines and spacing in the interior of the grid. The method is applied to a rectilinear wind-tunnel case and to two body shapes in spherical coordinates.
    Keywords: AERODYNAMICS
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  • 51
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    An orthogonal coordinate grid following the three-dimensional viscous flow over a concave surface (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Swept wings designed for laminar flow control exhibit both centrifugal and crossflow instabilities which produce streamwise vortices that can lead to early transition from laminar to turbulent flow in the presence of Tollmien-Schlichting waves. This paper outlines an iterative algorithm for generation of an orthogonal, curvilinear, coordinate grid following the streamlines of the three-dimensional viscous flow over a swept, concave surface. The governing equations for the metric tensor are derived from the Riemann-Christoffel tensor for an Euclidian geometry. Unit vectors along streamline, normal and binormal directions are determined. The governing equations are not solved directly, but are employed only as compatibility equations. The scale factor for the streamline coordinate is obtained by an iterative integration scheme on a 200 x 100 x 5 grid, while the other two scale factors are determined from definitions. Sample results are obtained which indicate that the compatibility equation error decreases linearly with grid step size. Grids smaller than 200 x 100 x 5 are found to be inadequate to resolve the grid curvature.
    Keywords: AERODYNAMICS
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  • 52
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    Investigation of tangential blowing applied to a subsonic V/STOL inlet (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 17, p. 2675, Accession no. A82-35195
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 20; 926-934
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  • 53
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    Applicability of the independence principle to subsonic turbulent flow over a swept rearward-facing step (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Prandtl (1946) has concluded that for yawed laminar incompressible flows the streamwise flow is independent of the spanwise flow. However, Ashkenas and Riddell (1955) have reported that for turbulent flow the 'independence principle' does not apply to yawed flat plates. On the other hand, it was also found that this principle may be applicable to many turbulent flows. As the sweep angle is increased, a sweep angle is reached which defines the interval over which the 'independence principle' is valid. The results obtained in the present investigation indicate the magnitude of the critical angle for subsonic turbulent flow over a swept rearward-facing step.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1603
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  • 54
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    Implicit, nonswitching, vector-oriented algorithm for steady transonic flow (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A rapid computation of a sequence of transonic flow solutions has to be performed in many areas of aerodynamic technology. The employment of low-cost vector array processors makes the conduction of such calculations economically feasible. However, for a full utilization of the new hardware, the developed algorithms must take advantage of the special characteristics of the vector array processor. The present investigation has the objective to develop an efficient algorithm for solving transonic flow problems governed by mixed partial differential equations on an array processor.
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1601-160
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  • 55
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    Time-dependent finite-difference simulation of unsteady interactive flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The solution of the time-dependent, Reynolds-averaged, Navier-Stokes equations for unsteady, interacting flows by finite-difference algorithms is discussed. Specific examples include (1) unsteady transonic flow over a thick biconvex airfoil, (2) determination of buffet boundaries for a transonic lifting airfoil, (3) the simulation of aileron buzz and (4) dynamic stall. Algorithms considered include explicit methods, mixed (or hybrid) methods, and fully implicit methods. Consideration of time scales for computational stability, computational accuracy, and physical accuracy and the use of time-dependent adaptive meshing to realize computational efficiency are also discussed.
    Keywords: AERODYNAMICS
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  • 56
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    Symposium on Numerical and Physical Aspects of Aerodynamic Flows, 2nd, California State University, Long Beach, CA, January 17-20, 1983, Proceedings (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The present conference covers topics concerning the measurement and calculation of interactive flows, together with problems posed by subsonic and transonic wings, missiles, and ships. Discussions are presented on the time-dependent finite difference simulation of unsteady interactive flows, Navier-Stokes equation methods, numerical solutions for spatially periodic boundary layers, the application of unsteady laminar tripple deck theory to viscous-inviscid interaction, the coupling of boundary layer and Euler equation solutions, and viscous-inviscid flow interactions. Also discussed are leading and trailing edge flows, three-dimensional wing flows, small disturbance calculations including entropy corrections, an inviscid computational method for tactical missiles, and boundary layer and flow separation characteristics of bodies of revolution at incidence.
    Keywords: AERODYNAMICS
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  • 57
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    Investigation of supersonic separated flow in a compression corner by laser Doppler anemometry (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A single-component, computer-operated, three dimensional traversing laser Doppler velocimetry system was designed and constructed for a supersonic wind tunnel. The model was a 10 deg compression corner, providing an example of laminar boundary layer separation. Static pressure data and color schlieren photographs were taken. The Mach number was 2.42 and the Reynolds number was 213,000. The flow was seeded with submicron sized oil droplets. The trend of decreasing upstream influence with increasing Reynolds number was confirmed. Mean velocity profiles provided experimental evidence of reversed flow. Points of separation and reattachment were consistent with those determined by schlieren and pressure scans. The flow was of the laminar type until downstream of reattachment. Individual mean velocity and turbulence profiles, as well as velocity histograms are presented.
    Keywords: AERODYNAMICS
    Type: Experiments in Fluids (ISSN 0723-4864); 1; 4, 19
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  • 58
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    Fire- and heat-resistant laminating resins based on maleimido-substituted aromatic cyclotriphosphazenes (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A novel class of flame- and heat-resistant polymers has been synthesized by the thermal polymerization of maleimido-substituted aromatic cyclotriphosphazenes. The polymer obtained from tris-(aminophenoxy)tris(maleimidophenoxy)cyclotriphosphazene has good thermal stability and is noteworthy for its high char yield, viz., 82 percent at 800 C in nitrogen and 81 percent at 700 C in air. Graphite-fabric laminates prepared with this polymer did not burn in pure oxygen, even at 300 C, and were tested for mechanical properties. Hexakis(4-maleimidophenoxy)cyclotriphosphazene and some fluorine-containing monomers have also been synthesized. The structures of these cyclic phosphazene precursors and polymers were characterized by FT IR spectrophotometry, H-1 NMR, F-19 NMR, and P-31 solid-state magic angle spinning NMR spectroscopy, and mass spectrometry. The curing behavior of the polymer precursors and the thermal stabilities of the polymers were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA).
    Keywords: NONMETALLIC MATERIALS
    Type: Macromolecules (ISSN 0024-9297); 16; 8, 19
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  • 59
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    Thermal response of advanced high temperature ceramic-composite insulation to a convectively heated environment (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Space Shuttle uses currently fibrous high temperature, reusable surface insulation (HRSI) as a Thermal Protection System (TPS) at 1260 C for normal-design mission operation. Higher density material of a similar type extended the maximum temperature to 1480 C. However, a surface temperature capability exceeding 1540 C is desired for future space vehicles, such as the Orbital Transfer Vehicle (OTV). A TPS providing such a capability would permit future entry vehicles to enter the atmosphere at a much higher velocity than the Space Shuttle. The present investigation is concerned with arc-jet test data obtained from a family of fibrous refractory-composite insulation (FRCI) materials developed to meet the future TPS requirements. FRCI materials containing between 20 and 80 percent aluminoborosilicate fibers with the balance composed of silica fibers were studied.
    Keywords: NONMETALLIC MATERIALS
    Type: Ceramic Engineering and Science Proceedings (ISSN 0196-6219); 4; 533-550
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  • 60
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    Fire resistant films for aircraft applications (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Alternative sandwich panel decorative films were investigated as replacements for the polyvinyl fluoride currently used in aircraft interiors. Candidate films were studied for flammability, smoke emission, toxic gas emission, flame spread, and suitability as a printing surface for the decorative acrylic ink system. Several of the candidate films tested were flame modified polyvinyl fluoride, polyvinylidene fluoride, polyimide, polyamide, polysulfone, polyphenylsulfone, polyethersulfone, polybenzimidazole, polycarbonate, polyparabanic acid, polyphosphazene, polyetheretherketon, and polyester. The films were evaluated as pure films only, films silk-screened with an acrylic ink, and films adhered to a phenolic fiberglass substrate. Films which exhibited the highest fire resistant properties included PEEK polyetheretherketon, Aramid polyamide, and ISO-BPE polyester. Previously announced in STAR as N83-22320
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Fire Sciences (ISSN 0734-9041); 1; 200-220
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    The efficient solution of transonic wing flow fields (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An evaluation of the transonic-wing-analysis computer code TWING is presented. TWING utilizes a fully implicit, approximate-factorization iteration scheme to solve the full-potential equation in conservative form. A numerical elliptic-solver grid-generation scheme is used to generate the required finite-difference mesh. Several wing configurations have been analyzed, and comparisons of computed results have been made with available experimental data. Results indicate that the code is robust, accurate (when significant viscous effects are not present), and efficient. TWING generally produces solutions an order of magnitude faster than other conservative, full-potential codes using successive-line overrelaxation. The present method is applicable to a wide range of isolated wing configurations, including high-aspect-ratio transport wings and low-aspect-ratio, high-sweep, fighter configurations.
    Keywords: AERODYNAMICS
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    Transonic small disturbance calculations including entropy corrections (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Murman's fully conservative mixed type finite-difference operators are first modified. A special sonic point operator with an iterative damping term is introduced which helps the convergence and does not affect the spatial conservative differences. Reliable calculations with second order supersonic schemes are obtained using two sonic operators, the regular sonic point operator followed by a first order supersonic scheme. Also, shock point operator is shown to be equivalent to fitting a locally normal shock terminating the supersonic region. The potential calculations are then modified to account for the non-isentropic jump conditions using a simple shock fitting procedure based on Prandtl relation. The entropy increase across the shock is calculated in terms of the Mach number upstream of the shock and the effect of the generated vorticity is estimated via Crocco relation. Different examples are calculated and extensions to the full potential equation are discussed.
    Keywords: AERODYNAMICS
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    Numerical simulation of turbulent trailing edge flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Numerical simulations of the time-dependent, Reynolds-averaged, Navier-Stokes equations, employing a two-equation turbulence model, are presented and compared with measurements from a series of trailing edge experiments at transonic Mach numbers. The test flows include an asymmetric flow with no separation, an asymmetric flow with a small region of separation and a symmetric flow with a large shock-wave induced separated zone. Comparisons are made for mean surface quantities as well as for mean and fluctuating flow-field quantities. For the trailing-edge flows with little or no separation, the solutions correctly predict all the major features of the flow field. Treatment of the viscous-inviscid interaction was found to be important for predicting these test cases. Two-equation eddy-viscosity turbulence models were found to be adequate for these flows. However, for the shock-wave induced separation case, these turbulence models were inadequate to predict this flow field. Modifications of the turbulence model to correct these deficiencies are discussed.
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  • 64
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    A basic design fault in ceramic flat packs (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Recent moisture resistance tests of various multilayer top brazed ceramic flat packs and leaded and unleaded chip carriers has revealed a serious design defect. These packages, which utilize a tungsten interconnect system, in the presence of high humidity, suffer a galvanic corrosion which anodically consumes the tungsten. This process can continue until the package suffers an open circuit. The test results indicate that the lead plating system does not adequately seal off the interface area where the tungsten stripe egresses from the inside of the package. Leaded and leadless chip carrier packages were also subjected to the moisture resistance test. The familiar red and green corrosion products were visible after the test was completed. Careful sectioning of the chip carriers has revealed that the tungsten interconnect stripe instead of exiting under the castellations, exits at the top of the castellation and is thus vulnerable to the attack of moisture. These basic design faults severely impact the reliability of these packages.
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  • 65
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    Resin characterization in cured graphite fiber reinforced composites using diffuse reflectance-FTIR (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The feasibility of using diffuse reflectance in combination with Fourier transform infrared spectroscopy to obtain information on cured graphite fiber reinforced polymeric matrix resin composites was investigated. Several graphite/epoxy, polysulfone, and polyimide composites exposed to thermal or radiation environments were examined. An experimental polyimide-sulfone adhesive tape was also studied during processing. In each case, significant changes in resin molecular structure was observed due to environmental exposure. These changes in molecular structure were correlated with previously observed changes in material properties providing new insights into material behavior.
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    Acetylene-terminated polyimide adhesives (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The nadic-encapped LARC-43 addition polyimide exhibits excellent flow, is easy to process, and can be utilized for short terms at temperatures up to 593 C. It retains good lap shear strength as an adhesive for titanium after aging in air up to 125 hours at 316 C; but lap shear strength degrades with longer exposures at that temperature. Thermid 600, an addition polyimide that is acetylene encapped, exhibits thermomechanical properties even after long term exposure in at air at 316 C. An inherent drawback of this system is that it has a narrow processing window. An acetylene encapped, addition polyimide which is a hybrid of these two systems was developed. It has good retention of strength after long term aging and is easily processed. The synthesis and characterization of various molecular weight oligomers of this system are discussed as well as the bonding, aging, and testing of lap shear adhesive samples. Previously announced in STAR as N83-18910
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  • 67
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    Maleimido substituted cyclotriphosphazene resins for fire and heat resistant composites (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new class of fire- and heat-resistant matrix resins have been synthesized by the thermal polymerization of maleimido substituted phenoxycyclotriphosphazenes. The resins have exhibited a char yield of 82 percent at 800 C in nitrogen and 81 percent at 700 C in air. Graphite-fabric laminates based on a resin of this class have shown a limiting oxygen index of 100 percent even at 300 C. Details of the fabrication of the resins and the composites and testing procedures are discussed.
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    A basic design fault in ceramic flat packs (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Recent moisture resistance tests of various multilayer top brazed ceramic flat packs and leaded and unleaded chip carriers has revealed a serious design defect. These packages, which utilize a tungsten interconnect system, in the presence of high humidity, suffer a galvanic corrosion which anodically consumes the tungsten. This process can continue until the package suffers an open circuit. The test results indicate that the lead plating system does not adequately seal off the interface area where the tungsten strips egresses from the inside of the package.
    Keywords: NONMETALLIC MATERIALS
    Type: SAMPE Quarterly (ISSN 0036-0821); 14; 28-32
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  • 69
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    Preliminary supersonic analysis methods including high angle of attack (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2343, Accession no. A82-31925
    Keywords: AERODYNAMICS
    Type: (ISSN 0021-8669)
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  • 70
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    Design of supercritical cascades with high solidity (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2343, Accession no. A82-31931
    Keywords: AERODYNAMICS
    Type: (ISSN 0001-1452)
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  • 71
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    Prediction of separated asymmetric trailing-edge flows at transonic Mach numbers (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 15, p. 2348, Accession no. A82-31974)
    Keywords: AERODYNAMICS
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  • 72
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    A finite-volume, adaptive grid algorithm applied to planetary entry flowfields (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2347, Accession no. A82-31971
    Keywords: AERODYNAMICS
    Type: (ISSN 0001-1452)
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  • 73
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    Turbulence modeling for computational aerodynamics (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 07, p. 965, Accession no. A82-19783
    Keywords: AERODYNAMICS
    Type: (ISSN 0001-1452)
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  • 74
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    Numerical solution of transonic wing flowfields (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 796, Accession no. A82-17785
    Keywords: AERODYNAMICS
    Type: (ISSN 0001-1452)
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  • 75
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    An empirical method for computing leeside centerline heating on the Space Shuttle Orbiter (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 17, p. 2880, Accession no. A81-39057
    Keywords: AERODYNAMICS
    Type: (ISSN 0022-4560)
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  • 76
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    Kinetics of crystallization of ZrF4-BaF2-LaF3 glass by differential scanning calorimetry (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society, Journal (ISSN 0002-7820); 66; April 19
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  • 77
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    Tribological properties of sintered polycrystalline and single-crystal silicon carbide (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously announced in STAR as N82-24343
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society Bulletin (ISSN 0002-7812); 62; April 19
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  • 78
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    Strength and fracture toughness of reaction-bonded Si3N4 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Fracture strength and fracture toughness measurements were made on reaction-bonded Si3N4 materials with a range of alpha/beta ratios. The results do not indicate any clear relation between the modulus of rupture and the alpha/beta ratio over the range 1.5-9. Values for the modulus of rupture range from 219 to 290 MN per sq m, with an overall average of 238 MN per sq m. The notched beam fracture toughness is found to be constant over the range of microstructures produced, indicating that of the various microstructural features (e.g., alpha/beta ratio and pore size and distribution) no single element has a controlling influence over fracture toughness and the fracture surface energy.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society Bulletin (ISSN 0002-7812); 62; April 19
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  • 79
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    Influence of leading-edge thrust on twisted and cambered wing design for suersonic cruise (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 20, p. 3457, Accession no. 81-43146
    Keywords: AERODYNAMICS
    Type: (ISSN 0021-8669)
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  • 80
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    Hypersonic slender-wedge analysis with gradual change in angle of attack (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The behavior of a narrow cross-section wedge wing moving at a high Mach number and subjected to an angle of attack changing exponentially with time is investigated. This type of wedge wing is commonly employed as a lifting surface in hypersonic vehicles. The time history of wall shear, heat transfer, displacement thickness, and viscous induced pressure are determined. Results show that for the same change in angle of attack, the flow attains the final steady state much faster when the change is exponential than when the change is made impulsively. In addition, the unsteady character of the flow is primarily confined to the initial stages of the change in the angle of attack.
    Keywords: AERODYNAMICS
    Type: Acta Mechanica; 47; 1-2,; 1983
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  • 81
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    Store separation from cavities at supersonic flight speeds (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 08, p. 1181, Accession no. A82-22096)
    Keywords: AERODYNAMICS
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  • 82
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    Oil flow separation patterns on an ogive forebody (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-10011)
    Keywords: AERODYNAMICS
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  • 83
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    Supercritical airfoil boundary-layer and near-wake measurements (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 22, p. 3806, Accession no. A81-45890)
    Keywords: AERODYNAMICS
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  • 84
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    Experimental studies of the vapor phase nucleation of refractory compounds. II - The condensation of an amorphous magnesium silicate (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Chemical Physics; 78; Feb. 1
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  • 85
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    Glass formation - A contemporary view (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The process of glass formation is discussed from several perspectives. Particular attention is directed to kinetic treatments of glass formation and to the question of how fast a given liquid must be cooled in order to form a glass. Specific consideration is paid to the calculation of critical cooling rates for glass formation, to the effects of nucleating heterogeneities and transients in nucleation on the critical cooling rates, to crystallization on reheating a glass, to the experimental determination of nucleation rates and barriers to crystal nucleation, and to the characteristics of materials which are most conducive to glass formation.
    Keywords: NONMETALLIC MATERIALS
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  • 86
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    Transonic airfoil calculations using solution-adaptive grids (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 16, p. 2685, Accession no. A81-37539)
    Keywords: AERODYNAMICS
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  • 87
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    Glass research in space (1983)
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    Publication Date: 2011-08-18
    Description: Opportunities and problems associated with conducting containerless glass experiments in a microgravity environment are examined. Particular aspects of gel-derived glasses for space processing research are discussed, along with current space-related research activities in areas of amorphous phase separation, crystallization, and heterogeneous and homogeneous crystal nucleation.
    Keywords: NONMETALLIC MATERIALS
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  • 88
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    Gels and gel-derived glasses in the system Na2O-B2O3-SiO2 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The containerless melting of high-purity multicomponent homogeneous gels and gel monoliths offers a unique approach to making ultrapure multicomponent optical glasses in the reduced gravity environment of space. Procedures for preparing and characterizing gels and gel-derived glasses in the system Na2O-B2O3-SiO2 are described. Preparation is based on the polymerization reactions of alkoxysilane with trimethyl borate or boric acid and a suitable sodium compound. The chemistry of the gelling process is discussed in terms of process parameters and the gel compositions. The physicochemical nature of gels prepared by three different procedures was found to be significantly different. Infrared absorption spectra indicate finite differences in the molecular structures of the different gels. The melting of the gel powders and the transformation of porous gel monoliths to transparent 'glass' without melting are described.
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  • 89
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    A method for solving the transonic full-potential equation for general configurations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 383-406
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  • 90
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    Elliptic grid generation for multi-element airfoils (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 1; p 337-34
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  • 91
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    Development of aerodynamic uncertainties for the Space Shuttle Orbiter (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 10, p. 1539, Accession no. A82-24653
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 20; 513-517
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  • 92
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    Orbiter entry leeside heat-transfer data analysis (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 05, p. 586, Accession no. A83-16745
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 20; 524-530
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  • 93
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    Augmentation of fighter-aircraft performance by spanwise blowing over the wing leading edge (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Spanwise blowing over the wing and canard of a 1:35 model of a close-coupled-canard fighter-airplane configuration (similar to the Kfir-C2) was investigated experimentally in low-speed flow. Tests were conducted at airspeeds of 30 m/sec (Reynolds number of 1.8 x 10 to the 5th power based on mean aerodynamic chord) with angle-of-attack sweeps from -8 deg to 60 deg, and yaw-angle sweeps from -8 deg to 36 deg at fixed angles of attack 0 deg, 10 deg, 20 deg, 25 deg, 30 deg, and 35 deg. Significant improvement in lift-curve slope, maximum lift, drag polar and lateral/directional stability was found, enlarging the flight envelope beyond its previous low-speed/maximum-lift limit. In spite of the highly swept (60 deg) leading edge, the efficiency of the lift augmentation by blowing was relatively high and was found to increase with increasing blowing momentum on the close-coupled-canard configuration. Interesting possibilities of obtaining much higher efficiencies with swirling jets were indicated.
    Keywords: AERODYNAMICS
    Type: AGARD Aerodyn. of Vortical Type Flows in Three Dimensions; 26 p
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  • 94
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    Recent studies at NASA-Langley of vortical flows interacting with neighboring surfaces (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: The importance of leading edge vortical flows, which occur near and interact with neighboring surfaces, is stressed. Research in this area conducted or sponsored by the NASA Langley Research Center since 1978 is surveyed. Particular attention is given to the cumulative results of a number of theoretical and experimental studies. It is noted that these studies have been carried out in order to understand and use this kind of flow. Much of the work has been devoted to improving the lift-to-drag ratio and pitch characteristics for wings in this flow, although work has also been done on examining the unsteady and lateral characteristics.
    Keywords: AERODYNAMICS
    Type: AGARD Aerodyn. of Vortical Type Flows in Three Dimensions; 32 p
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  • 95
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    Transonic Airfoil Development (1983)
    In:  CASI
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    Publication Date: 2017-10-02
    Description: This lecture consists of three parts, in which discussions are presented of the current state of development of transonic or supercritical airfoils designed for fully turbulent boundary layers on the surfaces, previous research on subcritical airfoils designed to achieve laminar boundary layers on all or parts of the surfaces, and current research on supercritical airfoils designed to achieve laminar boundary layers. In the first part the use of available two dimensional computer codes in the development of supercritical airfoils and the general trends in the design of such airfoils with turbulent boundary layers are discussed. The second part provides the necessary background on laminar boundary layer phenomena. The last part, which constitutes the major portion of the lecture, covers research by NASA on supercritical airfoils utilizing both decreasing pressure gradients and surface suction for stabilizing the laminar boundary layer. An investigation of the former has been recently conducted in fight using gloves on the wing panels of the U.S. Air Force F111 TACT airplane, research on the later is currently being conducted in a transonic wind tunnel which has been modified to greatly reduce the stream turbulence and noise levels in the tests section.
    Keywords: AERODYNAMICS
    Type: AGARD Spec. Course on Subsonic(Transonic Aerodyn. Interference for Aircraft; 9 p
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  • 96
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    Numerical predictions of residence times behind a rearward facing step with transverse injection (1983)
    In:  Other Sources
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    Publication Date: 2017-10-02
    Description: A numerical investigation of the two-dimensional recirculation zone formed between a rear-ward facing step and a transverse hydrogen jet in a supersonic flow is presented. Calculations were made using an elliptic flow computer code with a time-relaxation finite difference integration algorithm. Cases were examined for jet static pressures between 2 and 5 times mainstream with jets located 3 to 7 step heights downstream of the step. Nominal mainstream flow conditions were Mach 2.4 air at 1 atm pressure and 1000K (1800R) static temperature. Results in the form of mean properties in the recirculation zone and residence time are presented. Calculations of the decay of hydrogen mass from the steady state are presented for selected cases. The combustion potential for each case is assessed by comparison of computed conditions in the recirculation zone with the results from a well-stirred reactor theory.
    Keywords: AERODYNAMICS
    Type: APL The 20th JANNAF Combust. Meeting, Vol. 1; p 635-652
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  • 97
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    Numerical simulation of vortex breakdown by the vortex-filament method (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: The vortex-filament method was applied to the simulation of vortex breakdown. The principal vortex region was represented by multiple filaments, and an axial velocity component was induced by a spiral winding of the filaments. An accuracy check was performed for a cylindrical swirling flow with simple analytical expressions for the axial and theta velocities. The result suggests that the flow field can be simulated to any accuracy by increasing the number of filaments. An axisymmetric-type vortex breakdown was simulated, with experimental data serving as upstream conditions. The calculated axial- and theta-velocity contours show the breakdown of the vortex, including a rapid change in the vortex core, followed axially by a recovery zone and then a second breakdown. When three dimensional initial data are used the second breakdown appears to be of the spiral type in correspondence with experimental observations. The present method can easily be used to simulate other types of vortex breakdown or other vortex flows with axial velocity.
    Keywords: AERODYNAMICS
    Type: AGARD Aerodyn. of Vortical Type Flows in Three Dimensions; 13 p
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  • 98
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    The treatment of convected vortices in compressible potential flow (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A method is described for incorporating line vortices into the three dimensional compressible potential flow equation. A modified Biot-Savart law is used to compute a vortical velocity field, which is added to the gradient of the potential to form a total velocity. A rapidly converging approximate factorization (AFZ) scheme is then used to compute a potential such that the modified potential flow equation as well as the appropriate boundary conditions, based on total velocity, are satisfied. As part of a coupled iteration procedure, the positions of the line vortices are computed so that they convect with the total flow. The method is used to compute the field due to a single line vortex convecting past a wing. This represents an approximation of the effect of a canard or other lifting surface ahead of the wing, which sheds a tip vortex. It is seen that the flow field is substantially modified by the passage of the vortex. Unlike Euler equation schemes, which are also used to compute these flows, the solutions exhibit no numerical diffusion: The convected vortices retain their initial upstream width. Euler solutions, on the other hand, involve a vorticity which is numerically convected in an Eulerian frame and, unless extensive adaptive grid refinement is used they result in vortices with spread as they convect. Also, the potential flow method requires approximately two orders of magnitude less computing time and much less computer storage than the Euler methods.
    Keywords: AERODYNAMICS
    Type: AGARD Aerodyn. of Vortical Type Flows in Three Dimensions; 12 p
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  • 99
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    On issues concerning flow separation and vortical flows in three dimensions (1983)
    In:  CASI
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    Publication Date: 2017-10-02
    Description: Vortical flows in three dimensional configurations that are of typical interest to aerodynamicists and researchers in fluid mechanics are reviewed. A list of 10 issues was compiled to understanding complex vortical flows.
    Keywords: AERODYNAMICS
    Type: AGARD Aerodyn. of Vortical Type Flows in Three Dimensions; 31 p
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  • 100
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    Effects of long duration exposure to simulated space environment on nonmetallic materials properties (1983)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: Nonmetallic materials specimens from the Viking program were tested in situ invacuo after continuous thermal vacuum exposure from 1971/1972 to the present. Eleven tests were done on appropriate specimens of 30 materials; however, no single material received all the tests. Some specimens also were exposed to 1 or 2.5 MeV electrons at differing fluences before testing. Baseline exposure data is reported for graphite/epoxy specimens that were exposed to vacuum since 1974. These materials were transferred to the thermal vacuum storage facility for future in situ testing and irradiation. Thin G/E specimens were tensile tested after thermal-vacuum cycling exposure. Photomicrographic examinations and SEM analyses were done on the failed specimens.
    Keywords: NONMETALLIC MATERIALS
    Type: AGARD Environ. Effects on Mater. for Space Appl.; 14 p
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