Bubble-domain circuit wafer evaluation coil set

Coil structures have been designed to permit nondestructive testing of bubble wafers. Wafers can be electrically or optically inspected and operated from quasi-static frequency to maximum device operating frequency

Radar studies of bird migration

Observations of bird migration with NASA radars were made at Wallops Island, Va. Simultaneous observations were made at a number of radar sites in the North Atlantic Ocean in an effort to discover what happened to those birds that were observed leaving the coast of North America headed toward Bermuda, the Caribbean and South America. Transatlantic migration, utilizing observations from a large number of radars is discussed. Detailed studies of bird movements at Wallops Island are presented

Detection of H-alpha emission from the Magellanic Stream: evidence for an extended gaseous Galactic halo

We have detected faint, diffuse H$\alpha emission from several points along the Magellanic Stream, using the Rutgers Fabry--Perot Interferometer at the CTIO 1.5-m telescope. At points on the leading edges of the H I clouds MS II, MS III, and MS IV, we detect H$\alpha emission of surface brightness $0.37 \pm 0.02$ Rayleighs, $0.21 \pm 0.04$ R, and $0.20 \pm 0.02$ R respectively, corresponding to emission measures of 1.0 to 0.5 \cmsixpc. We have observed several positions near the MS IV concentration, and find that the strongest emission is on the sharp leading-edge density gradient. There is less emission at points away from the gradient, and halfway between MS III and MS IV the H$\alpha surface brightness is$< 0.04$R. We attribute the H$\alpha emission at cloud leading edges to heating of the Stream clouds by ram pressure from ionized gas in the halo of the Galaxy. These observations suggest that ram pressure from halo gas plays a large role in stripping the Stream out of the Magellanic Clouds. They also suggest the presence of a relatively large density of gas, $n_{\rm H} \sim 10^{-4} cm^{-3}$, in the Galactic halo at $\sim 50$ kpc radius, and far above the Galactic plane, $b \sim -80\deg$. This implies that the Galaxy has a very large baryonic, gaseous extent, and supports models of Lyman-$\alpha and metal-line QSO absorption lines in which the absorption systems reside in extended galactic halos.Comment: 15 pages, aaspp latex, + 1 table & 3 figures. Accepted in A.J. Also available from http://www.physics.rutgers.edu/~bweiner/astro/papers

Tracking radar studies of bird migration

The application of tracking radar for determining the flight paths of migratory birds is discussed. The effects produced by various meteorological parameters are described. Samples of radar scope presentations obtained during tracking studies are presented. The characteristics of the radars and their limitations are examined

Pyrolysis of brominated feedstock plastic in a fluidised bed reactor

Fire retarded high impact polystyrene has been pyrolysed using a fluidised bed reactor with a sand bed. The yield and composition of the products have been investigated in relation to fluidised bed temperature. The bromine distribution between the products and a detailed analysis of the oils using GC-FID/ECD, GC-MS, FT-ir, and size exclusion chromatography has been carried out. It was found that the majority of the bromine transfers to the pyrolysis oil and the antimony was detected in both the oil and the char. Oil made up over 89.9% of the pyrolysis products. Over 30% of the oil consisted of benzene, toluene, ethylbenzene, styrene and cumene. The pyrolysis gases were mainly hydrocarbons in the C1-C4 range but some HBr and Br2 was detected

Magnetic ionization fronts II: Jump conditions for oblique magnetization

We present the jump conditions for ionization fronts with oblique magnetic fields. The standard nomenclature of R- and D-type fronts can still be applied, but in the case of oblique magnetization there are fronts of each type about each of the fast- and slow-mode speeds. As an ionization front slows, it will drive first a fast- and then a slow-mode shock into the surrounding medium. Even for rather weak upstream magnetic fields, the effect of magnetization on ionization front evolution can be important. [Includes numerical MHD models and an application to observations of S106.]Comment: 9 pages, 10 figures, Latex, to be published in MNRA

Compression failure mechanisms in unidirectional composites

Compression failure mechanisms in unidirectional composites were examined. Possible failure modes of constituent materials are summarized and analytical models for fiber microbuckling are reviewed from a unified viewpoint. Due to deficiencies in available models, a failure model based on nonlinear properties and initial fiber curvature is proposed. The effect of constituent properties on composite compression behavior was experimentally investigated using two different graphite fibers and four different epoxy resins. The predominant microscopic scale failure mode was found to be shear crippling. In a soft resin, shear crippling was in the form of buckling of fibers on a microscopic scale. However, stiff resins failure was characterized by the formation of a kink band. For unidirectional laminates, compressive strength, and compressive modulus to a less extent, were found to increase with increasing magnitude of resin modulus. The change in compressive strength with resin modulus was predicted using the proposed nonlinear model

Explanation of the Tao effect

In a series of experiments Tao and coworkers\cite{tao1,tao2,tao3} found that superconducting microparticles in the presence of a strong electrostatic field aggregate into balls of macroscopic dimensions. No explanation of this phenomenon exists within the conventional theory of superconductivity. We show that this effect can be understood within an alternative electrodynamic description of superconductors recently proposed that follows from an unconventional theory of superconductivity. Experiments to test the theory are discussed.Comment: Submitted to Science January 2nd, declined January 6th; to Nature January 7th, declined January 13th; to PRL January 14th, declined February 25t

Comparison of toughened composite laminates using NASA standard damage tolerance tests

The proposed application of composite materials to transport wing and fuselage structures prompted the search for tougher materials having improved resistance to impact damage and delamination. Several resin/graphite fiber composite materials were subjected to standard damage tolerance tests and the results were compared to ascertain which materials have superior toughness. In addition, test results from various company and NASA laboratories were compared for repeatability