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Electron micrographs have been obtained which clearly show the existence of a void network in amorphous Ge films formed at substrate temperatures of 25 and 150 C, and the absence of a void network in films formed at higher substrate temperatures of 200 and 250 C. These results correlate quite well with density measurements and predictions of void densities by indirect methods.
Incoherent scatter and tilting filter photometer data from Arecibo Observatory were combined to search for a contribution to the 6300 A predawn enhancement due to impact excitation by photoelectrons from the magnetic conjugate point. Prior to about 105 deg conjugate solar zenith angle, calculations of the 6300 A intensities due to dissociative recombination gave good agreement with the observed intensities. Then, with the arrival of conjugate photoelectrons (confirmed by plasma line enhancements), the observed intensities rose above the calculated, the difference increasing until a plateau was achieved at a conjugate solar zenith angle of about 95 deg. The difference or residual intensity is attributed to direct photoelectron impact excitation. Significant day-to-day variations in the onset angle and intensity have a strong negative correlation with ionospheric electron density.
There are no author-identified significant results in this report. Evaluation has begun on ERTS-1 imagery of Crook County for use in landform interpretation and geologic mapping and interpretation. Outside of Crook County the geology team has been impressed by the display of fault patterns in southeastern Oregon and has begun preliminary analyses of these. Using the color combiner a complete timber type map of (1) all the forest land within Crook County, and (2) all the Ochoco National Forest has been completed. The timber types consist of five density classes which are correlated with different species compositions as the first step in the multistage forest inventory. Using the ERTS magnetic tape data the computer center has produced a 12 by 25 mile strip printout of bands 5, 6, and 7. The computer printouts are to be analyzed for different timber types and possible insect damage. Other results are: (1) limited number of clearcuts in eastern Oregon and in Cascades evident; (2) positive transparencies of band 5 appear to be too dark for maximum information of forested areas; and (3) much more information in the computer printouts of bands 6 and 7, than 5, when analyzing forest conditions.
An experimental investigation has been conducted to compare the results obtained with six different instruments that sense fluctuating quantities in free jets. These sensors are typical of those that have recently been used by various investigators who are engaged in experimental studies of jet noise. Intensity distributions and two-point correlations with space separation and time delay were obtained. The static pressure, density, and velocity fluctuations are well correlated over the entire cross section of the jet and the cross-correlations persist for several jet diameters along the flow direction. The eddies appear to be flattened in the flow direction by a ratio of 0.4.
A ground winds test was conducted on the Skylab 2 spacecraft in a subsonic wind tunnel and the results were tape recorded for analysis. The data reduction system used to analyze the tapes for full scale, first and second mode bending moments, or acceleration plots versus dynamic pressure or wind velocity is explained. Portions of the Skylab 2 tape data were analyzed statistically in the form of power spectral densities, autocorrelations, and cross correlations to introduce a concept of using system response decay as a measure of linear system damping.
The work consists of two parts. The first deals with the fine structure of radio pulses. Based on kinetic theory, processes occurring in the plasma shell of a pulsar when external electromagnetic radiation is present are investigated. It is shown that electromagnetic waves cause electrons to drift relative to ions, and initiate longitudinal oscillations. A dispersion equation describing the longitudinal oscillations in magnetized plasma is derived. Conditions for excitation of oscillations are found. Correlation functions of electron density are calculated, along with the coefficients of electromagnetic wave scattering. It is shown that variations in the amplitude of pulsar pulses are associated with scintillations caused by fluctuations in the plasma electron density. The second part of the study presents a mechanism for the radio emission of pulsars. The model of a rotating and a pulsating star, a neutron star with dipolar or more complex magnetic field, is examined.
A tabulation of selected altitude-correlated values of pressure, density, speed of sound, and coefficient of viscosity for each of six models of the atmosphere is presented in block data format. Interpolation for the desired atmospheric parameters is performed by using cubic spline functions. The recursive relations necessary to compute the cubic spline function coefficients are derived and implemented in subroutine form. Three companion subprograms, which form the preprocessor and processor, are also presented. These subprograms, together with the data element, compose the spline fit atmosphere package. Detailed FLOWGM flow charts and FORTRAN listings of the atmosphere package are presented in the appendix.
Analysis of Pc 3, 4 micropulsation wave forms recorded at Calgary in September 1969 shows a tendency toward signal enhancement in cases where the interplanetary magnetic field is at a small angle to the sun-earth line. Scatter plots of hourly Pc 3, 4 amplitudes exhibit a definite trend toward large signals when this angle is less than 50 or 60 degrees, and a corresponding disappearance of significant amplitudes when the angle is greater than 60 degrees. There is, however, an appreciable variability in individual cases. Power density spectrograms improved the correlation of pulsation strength with low angle in some cases.
Remote sensing of various coastal phenomena on the Kujukuri Coast and Kashimanada Coast was done by the use of aircraft for the purpose of investigating the characteristics of shore reefs and floating sand, and the depth of the sea. A multispectral camera and a video ITV camera were used as sensors. The first flight was over the Kashimanada and Kujukuri Coasts and the next flight was over the Katsuura Bay. The shape of shore reefs, the state of floating sand, the depth of the sea, etc., are represented by equidensitographs using texture. The interval of density slices is 0.05. Correlations between the textures represented by equidensitographs, digital graphs and analog display are estimated.
Coated, reinforced carbon-carbon (RCC) is used for the leading edges of the space shuttle. The mass loss characteristics of RCC specimens coated with tetraethyl orthosilicate (TEOS) were determine for conditions which simulated the environment expected at the lug attachment area of the leading edge. Mission simulation included simultaneous application of load, temperature, and oxygen partial pressure. Maximum specimen temperature was 900 K (1160 F). Specimens were exposed for up to 80 simulated missions. Stress levels up to 6.8 MPa (980 psi) did not significantly affect the mass loss characteristics of the TEOS-coated RCC material. Mass loss was correlated with the bulk density of the specimens.
The paper examines convection phenomena during the growth of sodium chlorate crystals from solution. Schlieren observations of sodium chlorate crystals suspended in supersaturated solutions showed that with increase in supersaturation or crystal size, the boundary layer on the side faces was stable while the top boundary layer and emerging plume changed from stable to partially oscillatory. The transition was a function of the Grashof number, Gr sub top, and the crystal height. Gr sub top correlated with plume width, number of streamlines, eddy density, and plume velocity, but the oscillation period correlated with the weight increase growth rate. The mass transfer rate, the linear growth rate, and growth of vertical and horizontal faces are discussed, and an estimate of boundary layer flow vs growth rate for near-critical stable convection indicated that growth of side faces depleted over half of the excess solute in the boundary layer. Impulse energies greatly in excess of the threshold value caused transient separation of the boundary layer on the top face, and plume wavering due to background-induced fluid motion was observed only at the lowest supersaturations.
An experimental investigation was conducted to determine the penetration of air jets d.irected perpendicularlY to an air stream. Jets Issuing from circular, square, and. elliptical orifices were investigated. and. the jet penetration at a position downstream of the orifice was determined- as a function of jet density, jet velocity, air-stream d.enaity, air-stream velocity, effective jet diameter, and. orifice flow coeffIcient. The jet penetrations were determined for nearly constant values of air-stream density at three tunnel-air velocities arid for a large range of Jet velocities and. densities. The results were correlated in terms of dimensionless parameters and the penetrations of the various shapes were compared. Greater penetration was obtained. with the square orifices and the elliptical orifices having an axis ratio of 4:1 at low tunnel-air velocities and low jet pressures than for the other orifices investigated. The square orifices gave the best penetrations at the higher values of tunnel-air velocity and jet total pressure.
The modal test program for the Galileo Spacecraft was completed at the Jet Propulsion Laboratory in the summer of 1983. The multiple sine dwell method was used for the baseline test. The Galileo Spacecraft is a rather complex 2433 kg structure made of a central core on which seven major appendages representing 30 percent of the total mass are attached, resulting in a high modal density structure. The test revealed a strong nonlinearity in several major modes. This nonlinearity discovered in the course of the test necessitated running additional tests at the unusually high response levels of up to about 21 g. The high levels of response were required to obtain a model verification valid at the level of loads for which the spacecraft was designed. Because of the high modal density and the nonlinearity, correlation between the dynamic mathematical model and the test results becomes a difficult task. Significant changes in the pre-test analytical model are necessary to establish confidence in the upgraded analytical model used for the final load verification. This verification, using a test verified model, is required by NASA to fly the Galileo Spacecraft on the Shuttle/Centaur launch vehicle in 1986.
The results of a survey of the soft X-ray sky in the C band (0.10-0.28keV) are reported. The observations were carried out using two independent flow proportional counters on board the SAS 3 X-ray satellite which had a total angular resolution of 2.9 deg FWHM, and a total exposure of 2.2 x 10 to the 4th per sq cm s sr. It is found that C band counting rates were generally inversely correlated with the column density of the neutral hydrogen on all angular scales down to the lowest angular resolution of the detectors. In the region 90-180 deg l and 0-10 deg b, the relation between C-band rates and the column densities of neutral hydrogen was fitted with a residual rms deviation of less than 13 percent by a two-component numerical model of the X-ray background. For the apparent attenuation column density a value of 2.7 x 10 to the 20th per sq cm was obtained. On the basis of a computer simulation of the SAS 3 data, it is shown that the observed clumping of interstellar matter was consistent with the magnitude of spatial fluctuations in the C-band map. When the background rates were subtracted from the survey map, the subsequent map showed foreground emission and absorption features with improved sensitivity and clarity. A series of computer-generated maps incorporating the SAS 3 data is given in an appendix.
Equilibrium, radiating viscous-shock-layer solutions are obtained for a number of trajectory points of the Fire II, Apollo 4, and PAET experimental flight vehicles. Convective heating rates calculated by a benchmark code agree well, except at high altitudes corresponding to low densities, with two engineering correlations. Calculated radiation intensities are compared with the flight radiometer data and with inviscid flow results. Differences as great as 70 percent are observed between measured data and the viscous calculations. Viscous effects reduce the intensity toward the wall, because of boundary-layer absorption, by as much as 30 percent, compared with inviscid intensities. Preliminary chemical and thermal nonequilibrium flow calculations along a stagnation streamline for a PAET trajectory predict enhancement of radiation owing to chemical relaxation. Stagnation point solutions are also presented for future air-assisted orbital transfer vehicle geometries with nose radii ranging from 0.3 to 15 m.
The effects of the mass and density of cool, heavy ion beams on the linear and nonlinear characteristics of right-hand resonant and nonresonant electromagnetic ion beam instabilities are analyzed. The magnetic helicity and Alfven speed for a computer simulated complete linear dispersion equation for electromagnetic instabilities are examined. The data reveal that the maximum growth rate of the resonant mode and the threshold velocity of the nonresonant mode decrease with beam mass; however, the maximum growth rate of the nonresonant mode and the threshold velocity of the resonant mode are independent of the beam mass. The role reversal of the instabilities which occur when a heavy ion beam is the more dense component is studied. The nonlinear behavior of the instabilities is described; variations in the magnetic field fluctuation levels and the beam mass dependence are investigated. It is observed that at low beam density the magnetic field fluctuation level increases with beam mass and at higher beam density the fluctuation level correlates with the core mass. The instability data are applied to observations of Venus and the Comet Giacobini-Zinner.
The He/H ratios in particle events associated with interplanetary travelling shocks are investigated. It is found that immediately after the arrival of the shock, the about 40 keV/nucl He/H flux ratio of energetic particles of equal velocity or equal energy per charge is correlated with the He/H density ratio in the solar wind. The ambient proton flux from the parent solar particle event appears to have a significant effect on the spectral shape of the shock-associated particle spectrum above 200 keV. These observations are consistent with a first-order Fermi acceleration of these particles in which the shock-heated solar wind is the principal contributor to the shock-associated particle population.
Wall pressure fluctuations were measured under the steady separation shock waves in Mach 5 turbulent interactions induced by unswept circular cylinders on a flat plate. The wall temperature was adiabatic. A conditional sampling algorithm was developed to examine the statistics of the shock wave motion. The same algorithm was used to examine data taken in earlier studies in the Princeton University Mach 3 blowdown tunnel. In these earlier studies, hemicylindrically blunted fins of different leading-edge diameters were tested in boundary layers which developed on the tunnel floor and on a flat plate. A description of the algorithm, the reasons why it was developed and the sensitivity of the results to the threshold settings, are discussed. The results from the algorithm, together with cross correlations and power spectral density estimates suggests that the shock motion is driven by the low-frequency unsteadiness of the downstream separated, vortical flow.