NASA-tricot - A lightweight radar reflective, knitted fabric

Fabric knitted on conventional knitting machines uses commercially available yarns, has high aerodynamic drag capability, and is relatively inexpensive. The two yarn components used are 15-denier nylon monofilament and aluminized Mylar tape

Lightweight inflatable material with low permeability

Material features combination of Mylar, for strength, and Saran, for impermeable qualities. Second lamination of Mylar prevents blocking, adds strength, and increases barrier rating. Different combinations of laminations produce variety of thicknesses and barrier ratings. Material can be metallized for increased barrier reliability and radar reflectivity, and can be treated with a heat-resistant coating

An X-ray survey of 9 algol systems

The observed X-ray luminosities seen from an Einstein survey of nine Algol like systems are similar to those found by Pallavicini, et al. (1981) for single or widely separated rapidly rotating late stars, but fall an order of magnitude below those seen from RS CVn stars with similar orbital periods and spectral types. It is concluded that the X-ray emission is most probably associated with a hot coronae surrounding the secondary. Possible explanations for the lower luminosity of the Algol systems relative to the RS CVn systems are considered

The 805s X-ray pulsar H2252-035

The X-ray flux from the 3.6 hr binary system H2252-035 is shown to be modulated at a period of 805s. The spectrum is consistent with either a 1.4 photon index power law or 20 keV thermal model. A 560t0r-350 eV equivalent width iron line is seen at approximately 6.7 keV. The possibility that this system contains a slowly rotating neutron star is discussed

Lightweight, variable solidity knitted parachute fabric

A parachute fabric for aerodynamic decelerator applications is described. The fabric will permit deployment of the decelerator at high altitudes and low density conditions. The fabric consists of lightweight, highly open, circular knitted parachute fabric with ribbon-like yarns to assist in air deflection

The COBE Normalization for Standard CDM

The COBE detection of CMB anisotropies provides the best way of fixing the amplitude of fluctuations on the largest scales. This normalization is usually given for an n=1 spectrum, including only the anisotropy caused by the Sachs- Wolfe effect. This is certainly not a good approximation for a model containing any reasonable amount of baryonic matter. In fact, even tilted S-W spectra are not a good fit to models like CDM. Here we normalize standard CDM (sCDM) to the 2-year COBE data, and quote the best amplitude in terms of the conventionally used measures of power. We also give normalizations for some specific variants of this standard model, and we indicate how the normalization depends on the assumed values of n, Omega_B and H_0. For sCDM we find =19.9\pm1.5uK, corresponding to sigma_8=1.34\pm0.10, with the normalization at large scales being B=(8.16\pm1.04)\times10^5 (Mpc/h)^4, and other numbers given in the Table. The measured rms temperature fluctuation smoothed on 10deg is a little low relative to this normalization. This is mainly due to the low quadrupole in the data: when the quadrupole is removed, the measured value of sigma(10) is quite consistent with the best-fitting . The use of should be preferred over sigma(10), when its value can be determined for a particular theory, since it makes full use of the data.Comment: 4 pages compressed uuencoded postscript. We have corrected an error in our analysi

Diffusion and phase change characterization by mass spectrometry

The high temperature diffusion of trace elements in metals and alloys was investigated. Measurements were made by high sensitivity mass spectrometry in which individual atoms were detected, and quantitative data was obtained for zircaloy-2, 304 stainless steel, and tantalum. Additionally, a mass spectrometer was also an analytical tool for determining an allotropic phase change for stainless steel at 955 C, and a phase transition region between 772 C and 1072 C existing for zircaloy-2. Diffusion rates were measured in thin (0.001" (0.0025 cm) and 0.0005" (0.0013 cm)) ribbons which were designed as high temperature thermal ion sources, with the alkali metals as naturally occurring impurities. In the temperature and pressure regime where diffusion measurements were made, the solute atoms evaporated from the ribbon filaments when the impurities diffused to the surface, with a fraction of these impurity atoms ionized according to the Langmuir-Saha relation. The techniques developed can be applied to many other alloys important to space vehicles and supersonic transports; and, with appropriate modifications, to the diffusion of impurities in composites

A 2 component X-ray spectrum from SMC X-1

Both HEAO-1 A2 and Einstein SSS observations of SMC X-1 are presented. An unpulsed soft component is found with a blackbody temperature of 0.16 keV and an area for the emission region of 10 to the 15th power sq cm to 10 to the 17th power sq cm. The hard X-ray component is pulsed; the phase averaged spectrum is a power law with alpha approximately 0.5 keV up to 17 keV above which it steepens. The SSS sets an upper limit of 4 x 10 to the 21st power H cm/2 to any absorption and is consistent with that expected from the wind of SK160. Absorption dips with a timescale of several hundred seconds are seen immediately following an eclipse exit and are probably caused by inhomogeneities in the wind of SK160

A numerical method for determining the natural vibration characteristics of rotating nonuniform cantilever blades

A method is presented for determining the free vibration characteristics of a rotating blade having nonuniform spanwise properties and cantilever boundary conditions. The equations which govern the coupled flapwise, chordwise, and torsional motion of such a blade are solved using an integrating matrix method. By expressing the equations of motion and matrix notation, utilizing the integrating matrix as an operator, and applying the boundary conditions, the equations are formulated into an eigenvalue problem whose solutions may be determined by conventional methods. Computer results are compared with experimental data