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  • Other Sources  (1,111)
  • AERODYNAMICS  (821)
  • Biochemistry and Biotechnology
  • Inorganic Chemistry
  • NONMETALLIC MATERIALS
  • 1980-1984  (1,111)
  • 1925-1929
  • 1983  (657)
  • 1980  (454)
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  • 1980-1984  (1,111)
  • 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)
    In:  Other Sources
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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)
    In:  Other Sources
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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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    Three-layer interactive method for computing supersonic laminar separated flows (1980)
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    Publication Date: 2011-08-18
    Description: An interactive model for numerical computation of complicated two-dimensional flowfields including regions of reversed flow is proposed. The present approach is one of dividing the flowfield into three regions, in each of which a simplified mathematical model is applied: (1) outer, supersonic flow for which the full potential equation (hyperbolic) is used; (2) viscous, laminar layer in which the compressible boundary-layer model (parabolic) is used; and (3) recirculating flow modeled by the incompressible Navier-Stokes equations (elliptic). For matching of the numerical solutions in the three layers, two interaction models are developed: one for pressure interaction, the other for interaction between the shear layer and the recirculating flow. The uniform solution for the whole flowfield is then obtained by iteration of the local solutions under the constraints imposed by matching. The three-layer interactive model is used for solution of the flowfield past an asymmetric cavity. The method is shown to be capable of dealing with backflow without encountering problems at separation, characteristic to the boundary-layer approach.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; Nov. 198
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  • 26
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    Thermal stability and aging of some new anaerobic adhesives for structural binding (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Polyurethane-modified high impact anaerobic adhesives have been chosen for a bonding application where impact cushion is critical. These adhesives meet all the requirements for high rate production and automatic assembly techniques. With aluminum adherends, one selected adhesive cured at room temperature with the recommended activator retained sixty percent of its original impact strength after twenty-six week aging at 100 C. The impact strength aging, the thermogravimetric analysis results, the outgassing data, and other observations made in this work indicate that the adhesives cured by simple heating give a more durable bond than that cured with an activator at room temperature.
    Keywords: NONMETALLIC MATERIALS
    Type: SAMPE Quarterly; 11; July 198
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  • 27
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    Synthesis of perfluoroalkylether triazine elastomers (1980)
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    Publication Date: 2011-08-17
    Description: A method of perfluoroalkylether triazine elastomer synthesis is described. To form an elastomer, the resultant polymer is heated in a closed oven at slightly reduced pressures for 1-day periods at 100, 130 and 150 C. A high-molecular-weight perfluoroalkylether triazine elastomer is produced that exhibits thermal and oxidative stability. This material is potentially useful in applications such as high-temperature seals, 'O' rings, and wire enamels.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Polymer Science; vol. 18
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  • 28
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    Release-rate calorimetry of multilayered materials for aircraft seats (1980)
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    Publication Date: 2011-08-17
    Description: Multilayered samples of contemporary and improved fire-resistant aircraft seat materials were evaluated for their rates of heat release and smoke generation. Top layers with glass-fiber block cushion were evaluated to determine which materials, based on their minimum contributions to the total heat release of the multilayered assembly, may be added or deleted. The smoke and heat release rates of multilayered seat materials were then measured at heat fluxes of 1.5 and 3.5 W/cm2. Abrasion tests were conducted on the decorative fabric covering and slip sheet to ascertain service life and compatibility of layers
    Keywords: NONMETALLIC MATERIALS
    Type: SAMPE Quarterly; 11; Apr. 198
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  • 29
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    Noise radiation from the side edges of flaps (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The recently observed phenomenon of high noise radiation from the side edges of flaps in flow is investigated by way of a simple two-dimensional model problem. The model is based upon a physical picture of boundary layer vorticity being swept around the edge by spanwise flow on the flap. The model problem is developed and solved and the resulting noise radiation calculated. Further, a mathematical condition for the vortex to be captured by the potential flow and swept around the edge is derived. The results show that the sound generation depends strongly upon the strength of the vorticity and distance from the edge and that it can be more intense than the more common trailing edge noise source in agreement with the experimental observations.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; May 1980
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  • 30
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    Stability aspects of diverging subsonic flow (1980)
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    Publication Date: 2011-08-17
    Description: The paper describes the computation of two-dimensional, subsonic, diverging internal flows and how they differ from the corresponding converging flows. Such diverging or decelerating flows occur in such obvious places as subsonic diffusers and inlets; however, such flows also occur in supersonic nozzles in the presence of a normal shock. The flow instability and its relation to the numerical method used, boundary conditions, and viscous effects are assessed both analytically and numerically. The inviscid flow is shown to be physically unstable and a poor representation of the true viscous flow.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; May 1980
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  • 31
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    Dissolution of multicomponent bubbles (1980)
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    Publication Date: 2011-08-18
    Description: The behavior of an isolated, stationary, multicomponent gas bubble in a glassmelt containing several dissolved gases is considered. The relevant mass-transport equations are formulated and calculations are performed for the case of two diffusing gases using a quasi-stationary model and a numerical solution of the exact mass-transfer equations. The results obtained from these two approaches are compared. The factors which govern the dissolution or growth of a bubble are thermodynamic and kinetic in origin. The tendency of a bubble to grow or shrink at long times is controlled by departure from overall equilibrium, whereas the short-time bubble dynamics may be dominated by kinetic effects. As a result of the existence of these dual influences, maxima and/or minima occur in the functional dependence of the bubble radius on time.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society; vol. 63
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  • 32
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    Photosensitized oxidation of unsaturated polymers (1980)
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    Publication Date: 2011-08-17
    Description: A review of the photosensitized oxidation of singlet oxygenation of unsaturated hydrocarbon polymers and of their model compounds is presented. The cis and trans forms of 1,4-polyisoprene, 1,4-polybutadiene and 1,2-poly(1,4-hexadiene) are studied, and their microstructural changes which occur on reaction with (IO2) in solution were investigated by infrared, (H-1) and (C-13) NMR spectroscopy. The polymers yielded allylic hydroperoxides with shifted double bonds according to the 'ene' mechanism of simple olefins. It was shown that single oxygenation of unsaturated polymers is similar to their low molecular weight analogs, and that the differences are due to secondary processes affecting the (IO2)-reacted polymers.
    Keywords: NONMETALLIC MATERIALS
    Type: Pure and Applied Chemistry; 52; 1980
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  • 33
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    Computational aerodynamics on large computers (1980)
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    Publication Date: 2011-08-17
    Description: Three examples of advances in computational aerodynamics; (1) three-dimensional inviscid transonic analysis, (2) design calculations for wings, and (3) the computation of viscous-induced aileron buzz, are reviewed. Attention is given to wing surface pressures, design optimization, computer memory, speed and advanced solution methods on parallel computer architecture. It is determined that many implicit approximate-factorization schemes, that have been developed for Navier-Stokes equations, can be coded to run efficiently on microprocessors.
    Keywords: AERODYNAMICS
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  • 34
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    Wing flapping with minimum energy (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A technique employed by Prandtl and Munk is adapted for the case of a wing in flapping motion to determine its lift distribution. The problem may be reduced to one of minimizing induced drag for a specified and periodically varying bending moment at the wing root. It is concluded that two wings in close tandem arrangement, moving in opposite phase, would eliminate the induced aerodynamic losses calculated
    Keywords: AERODYNAMICS
    Type: Aeronautical Journal; 84; July 198
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  • 35
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    Performance of Chevron-notch short bar specimen in determining the fracture toughness of silicon nitride and aluminum oxide (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Ease of preparation and testing are advantages unique to the chevron-notch specimen used for the determination of the plane strain fracture toughness of extremely brittle materials. During testing, a crack develops at the notch tip and extends stably as the load is increased. For a given specimen and notch configuration, maximum load always occurs at the same relative crack length independent of the material. Fracture toughness is determined from the maximum load with no need for crack length measurement. Chevron notch acuity is relatively unimportant since a crack is produced during specimen loading. In this paper, the authors use their previously determined stress intensity factor relationship for the chevron-notch short bar specimen to examine the performance of that specimen in determining the plane strain fracture toughness of silicon nitride and aluminum oxide.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Testing and Evaluation; 8; May 1980
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  • 36
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    The effect of finite turbulence spatial scale on the amplification of turbulence by a contracting stream (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The turbulence downstream of a rapid contraction is calculated for the case when the turbulence scale can have the same magnitude as the mean-flow spatial scale. The approach used is based on the formulation of Goldstein (1978) for turbulence downstream of a contraction, with the added assumptions of a parallel mean flow at downstream infinity and turbulence calculated far enough downstream so that the nonuniformity of the mean flow field has decayed, and by treating the inverse contraction ratio as a small parameter. Consideration is given to the large-contraction-ratio and classical rapid-distortion theory limits, and to results at an arbitrary contraction ratio. It is shown that the amplification effect of the contraction is reduced when the spatial scale of the turbulence increases, with the upstream turbulence actually suppressed for a contraction ratio less than five and a turbulence spatial scale greater than three times the transverse dimensions of the downstream channel.
    Keywords: AERODYNAMICS
    Type: Journal of Fluid Mechanics; 98; June 12
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  • 37
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    Fracture toughness determination of Al2O3 using four-point-bend specimens with straight-through and chevron notches (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society; vol. 63
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  • 38
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    Types of leeside flow over delta wings (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: It is noted that so far most systematic investigations on the lee side flow over delta wings at supersonic speeds are concerned with flat upper surfaces. On the basis of these results, the paper makes an attempt to characterize the different types of flow over a wing with a delta-shaped upper surface by varying a number of parameters. It is concluded that the work should be considered a first step toward systematizing the flow over delta-shaped lee sides as well.
    Keywords: AERODYNAMICS
    Type: Zeitschrift fuer Flugwissenschaften und Weltraumforschung; 4; Mar
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  • 39
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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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  • 40
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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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  • 41
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    Characteristics of Si3N4-SiO2-Ce2O3 compositions sintered in high-pressure nitrogen (1983)
    In:  Other Sources
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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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  • 42
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    Behavior of bubbles in glassmelts. II - Dissolution of a stationary bubble containing a diffusing and a nondiffusing gas (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The effect of a foreign nondiffusing gas on the rate of shrinkage of an oxygen bubble in a soda-lime-silica melt was studied. The rate of change of bubble radius with time was computed using the quasi-stationary approximation. The effects of melt undersaturation and initial fraction of foreign gas in the bubble are considered and compared with those calculated using previously derived expressions.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society; vol. 63
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  • 43
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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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  • 44
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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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  • 45
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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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  • 46
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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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  • 47
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    Lower-curing-temperature PMR polyimides (1983)
    In:  Other Sources
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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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  • 48
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    Dynamic fatigue of a machinable glass-ceramic (1983)
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    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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  • 49
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    Experimental determination of vapor species from laser-ablated carbon phenolic composites (1983)
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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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  • 50
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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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  • 51
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    Cavitation erosion characteristics of poly(methyl methacrylate) in a rotating disk device (1983)
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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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  • 52
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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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  • 53
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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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  • 54
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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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  • 55
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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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  • 56
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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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  • 57
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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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  • 58
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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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  • 59
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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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  • 60
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    Oxygen index tests of thermosetting resins (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The flammability characteristics of nine thermosetting resins under evaluation for use in aircraft interiors are described. These resins were evaluated using the Oxygen Index (ASTM 2863) testing procedure. The test specimens consisted of both neat resin and glass reinforced resin. When testing glass-reinforced samples it was observed that Oxygen Index values varied inversely with resin content. Oxygen values were also obtained on specimens exposed to temperatures up to 300 C. All specimens experienced a decline in Oxygen Index when tested at an elevated temperature.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Fire and Flammability; 11; Jan. 198
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  • 61
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    Carbon fiber production at low temperatures from polyacrylonitrile (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Recent safety considerations have sought to lower the electrical conductivity of carbon fibers. Carbon fibers produced from polyacrylonitrile at low carbonization temperatures (600-900 C) possess low electrical conductivity but do not possess adequate strength. Low-temperature processes are described which improve fiber strength but do not increase electrical conductivity substantially. The processes result in a carbon fiber with nearly twice the tensile strength compared to the old process. Process development and its effect on fiber properties are reported.
    Keywords: NONMETALLIC MATERIALS
    Type: Textile Research Journal; 50; Oct. 198
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  • 62
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    Developments in fibrous refractory composite insulation (1980)
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    Publication Date: 2011-08-18
    Description: The development of a new insulation material for heat-shielding advanced reusable entry vehicles is reported. The material, called fibrous refractory composite insulation, is a composite of two ceramic fibers with no additional additives to bond the fibers together; it also includes silicon carbide, an emmittance agent, to improve its optical properties at high temperature. One fiber is a drawn 11-micron-diameter aluminoborosilicate fiber, the other fiber is the silica fiber (microquartz) used in producing silica RSI (reusable surface insulation for the Space Shuttle), which is a blown fiber of 1-3 micron diameter and variable length. A composition containing 20%, with a thermal shock resistance of 1.8 that of all silica insulation, has been successfully produced in a pilot plant.
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  • 63
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    Comparative evaluation of insulating properties of plasma-sprayed ceramic coatings (1980)
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    Publication Date: 2011-08-18
    Description: A simple method for evaluating the thermal insulating capability of ceramic coatings was devised. It is based on monitoring the temperature of the uncoated back surface of a thin superalloy disk while its front surface, coated with the ceramic material, is exposed to the high-temperature environment of an electric muffle furnace. The results obtained indicate that zirconia containing 8 wt% Y2O3 is a better thermal insulator than barium zirconate or calcium orthosilicate.
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  • 64
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    Thin-layer approximation for three-dimensional supersonic corner flows (1980)
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    Publication Date: 2011-08-18
    Description: The thin-layer approximation is extended to an axial corner that is formed by the intersection of two perpendicular plates, one of which has an inclination angle with respect to the free stream. A computer code developed by Hung and MacCormack (1978) is modified for the thin-layer approximation, and a case with Mach 5.9 and a wedge angle of 6 deg is computed. In addition, it is shown that it is not necessary to solve the complete Navier-Stokes equations for a three-dimensional high-Reynolds-number corner flow.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; Dec. 198
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  • 65
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    Determination of the orientation symmetry axis of graphite specimens (1980)
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    Publication Date: 2011-08-18
    Description: A technique is described for determining the true orientation symmetry axis of graphite specimens from conventional X-ray diffraction data. The technique, although developed for graphite, is applicable to any material exhibiting crystalline orientation which is symmetric about some axis. The requisite equations are derived for applying the procedure to both Bacon transmission data and rotating specimen reflection data. Results are presented which show that the symmetry axis of eleven molded graphites tested differed significantly from their nominal pressing directions.
    Keywords: NONMETALLIC MATERIALS
    Type: Carbon; 18; 3-E,; 1980
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  • 66
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    Flowfield calculations past an entry probe with ablated nose shape (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The effects of ablated nose shapes on the flowfield solutions are studied, using a time-dependent finite-difference method developed by Kumar, et al. (1979). Solutions are obtained for the laminar flow of a radiating mixture of H-He in chemical equilibrium past a blunt axisymmetric body at zero angle of attack. The freestream conditions correspond to a point on a typical Jovian entry trajectory, and the initial probe shape is a 45-deg half-angle spherically blunted cone. It is found that as nose bluntness increases, the following occur: in the nose region, shock standoff distances and radiative heating rates increase substantially; surface pressure level increases, but convective heating rates decrease.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; June 198
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  • 67
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    Unified treatment of lifting atmospheric entry (1980)
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    Publication Date: 2011-08-17
    Description: This paper presents a unified treatment of the effect of lift on peak acceleration during atmospheric entry. Earlier studies were restricted to different regimes because of approximations invoked to solve the same transcendental equation. This paper shows the connection between the earlier studies by employing a general expression for the peak acceleration and obtains solutions to the transcendental equation without invoking the earlier approximations. Results are presented and compared with earlier studies where appropriate.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 17; Mar
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  • 68
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    Linear/nonlinear behavior in unsteady transonic aerodynamics (1983)
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 12, p. 1923, Accession no. A81-29496)
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  • 69
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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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  • 70
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    Computation of nonequilibrium, supersonic three-dimensional inviscid flow over blunt-nosed bodies (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2120, Accession no. A75-33931
    Keywords: AERODYNAMICS
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  • 71
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    Separated trailing-edge flow at a transonic Mach number (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 800, Accession no. A82-17899
    Keywords: AERODYNAMICS
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  • 72
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    Unsteady transonic small disturbance approximation with strong shock waves (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 797, Accession no. A82-17812
    Keywords: AERODYNAMICS
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  • 73
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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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  • 74
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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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  • 75
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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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  • 76
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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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  • 77
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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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  • 78
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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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  • 79
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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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  • 80
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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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  • 81
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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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  • 82
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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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  • 83
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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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  • 84
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    The efficient solution of transonic wing flow fields (1983)
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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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  • 85
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    Transonic small disturbance calculations including entropy corrections (1983)
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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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  • 86
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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.
    Keywords: AERODYNAMICS
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  • 87
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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.
    Keywords: NONMETALLIC MATERIALS
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  • 88
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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.
    Keywords: NONMETALLIC MATERIALS
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  • 89
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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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  • 90
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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.
    Keywords: NONMETALLIC MATERIALS
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  • 91
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    Unknown
    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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  • 92
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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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  • 93
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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
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  • 94
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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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  • 95
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    A finite-volume, adaptive grid algorithm applied to planetary entry flowfields (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 15, p. 2347, Accession no. A82-31971
    Keywords: AERODYNAMICS
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  • 96
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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
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  • 97
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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
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  • 98
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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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  • 99
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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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  • 100
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    Tribological properties of sintered polycrystalline and single-crystal silicon carbide (1983)
    In:  Other Sources
    Details
    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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